Symposium Organizers
Todd C. Monson, Sandia National Laboratories
Enzo Ferrara, Istituto Nazionale di Ricerca Metrologica
Mitra Taheri, Drexel University
Torbjorn Thiringer, Chalmers University of Technology
Symposium Support
U.S. Department of Energy-Office of Electricity Delivery and Energy Reliability
U.S. Department of Energy-Office of Electricity Delivery and Energy Reliability Energy Storage Program
Sandia National Laboratories
ES12.1: Soft Magnetic Materials for Next-Generation Power Electronics I
Session Chairs
Enzo Ferrara
Todd C. Monson
Wednesday PM, April 19, 2017
PCC North, 200 Level, Room 227 C
10:00 AM - *ES12.1.01
Enabling Wide Band Gap Devices Based Power Converters Applications by High Frequency Magnetics
Subhashish Bhattacharya 1
1 Department of ECE, FREEDM Systems Center and PowerAmerica Institute, North Carolina State University, Raleigh, North Carolina, United States
Show AbstractThe advent of WBG (SiC and GaN) power semiconductor devices is poised to revolutionize the power electronics applications – both in the low power and low voltage applications as well as the Medium Voltage (MV) and High Voltage (HV) applications at high power levels. WBG power semiconductor devices enable higher voltages, higher switching frequency and higher temperature operation compared to Si power semiconductor devices. To enable WBG devices based power converters applications, high frequency magnetics is imperative with desired characteristics of higher saturation flux densities, lower losses and predictable operation under wide temperature variations. The specifications of the core materials and their electrical characterization with suitable high frequency test circuits will be enumerated. The impact of these results on the design of high frequency magnetics and parasitic capacitances will be discussed.
This paper outlines opportunities for HV SiC devices for MV Power Converters and utility applications and the challenges to apply these HV SiC devices successfully, with SiC device voltage ranges from 1200 V to 1700 V MOSFETs, and JBS diodes through HV 10 kV - 15 kV MOSFETs, JBS diodes, and 15 kV SiC IGBTs. The potential and challenges of the HV 10-15 kV devices to enable MV power conversion systems, including the large market space of MV motor drives will be explored in detail. The comparison with HV Si-IGBTs (6.5 kV, 4.5 kV and 3.3 kV) with the HV and high frequency SiC devices for various MV power conversion applications will also be enumerated. The utility applications area of FACTS and VSC based HVDC and in particular MVDC systems can be enabled by these HV SiC devices. Challenges in adopting these HV SiC devices for MV power conversion in terms of magnetics, capacitors, insulation materials and impact on lifetime through dielectric losses will also be discussed.
10:30 AM - ES12.1.02
Novel Bulk Metallic Glass, Fe-Co-Si-B-P, with Good Soft Magnetic Properties and High Glass Forming Ability
Michael Floyd 1 , Marios Demetriou 1 , William Johnson 1
1 Materials Science, California Institute of Technology, Pasadena, California, United States
Show AbstractA bulk ferromagnetic glass with composition Fe57Co20Si7.5B5.5P10 is developed, demonstrating a high glass forming ability and excellent soft-magnetic properties. In spite of the exclusion of nonferrous transition metals, amorphous rods up to 5 mm can be cast through the use of a refined fluxing procedure. The cobalt concentration is optimized for glass forming ability and coincides with a peak in the Slater-Pauling curve. This results in a magnetic saturation of 1.53T, coercivity of 2.3 A/m, relative permeability of 37,932, and Curie temperature of 730 K for the annealed glass. This is the best combination of magnetic saturation and glass forming ability for a ferromagnetic metallic glass reported to date.
11:15 AM - *ES12.1.03
Advanced Soft Magnetic Materials for High Power Density, High Efficiency Electrical Systems
Francis Johnson 1
1 , GE Global Research, Niskayuna, New York, United States
Show AbstractElectrical power generation, distribution, and conversion systems are key components of infrastructure technology in several industrial sectors. There is continual demand for electrical systems with higher power density that must also meet aggressive efficiency and reliability requirements. Advanced magnetic materials are critical to the performance of these systems. The complementary needs of high power density and high system efficiency demand components that exhibit low power loss at high frequencies. The trend in power conversion technology is to move away from low frequency transformers to modular power electronic systems with high frequency transformers. New magnetic materials are under development that are operable from the MW-level-20 kHz range up to the kW-level -MHz range with operating temperatures up to 300 °C. Examples will be presented of thermally stable bulk amorphous soft magnetic alloys that can be formed into thin cross sections to minimize eddy current losses at high frequencies. Inductive devices produced by nanostructured thick film deposition will also be discussed as alternatives for HF and VHF power electronic systems. Advanced electric machines and drives are being developed to operate at continually higher speeds and temperatures. Novel machine architectures are enabled by newly developed alternatives to traditional electrical steels and rare earth permanent magnets. Advances in the processing of crystalline soft magnetic steels will be discussed that can enable rare-earth-free electric machine topologies to match the performance of machine architectures that depend on permanent magnets. Strategies for improved magnetic material performance will be discussed that include nanoscale structure control, novel device geometries, new alloy and compound development, and improved processing methods to maintain a sustainable value chain.
11:45 AM - *ES12.1.04
Nanococrystalline/Amorphous Nanocomposite Based Alloy and Core Development and Integration in Soft Magnetics for Emerging Wide Bandgap Power Electronics Based Converters
Paul Ohodnicki 1 2 , Alex Leary 2 , Vladimir Keylin 2 , Michael McHenry 2 , Richard Beddingfield 3 , Ritwik Chattopadhyay 3 , Ghanshyam Gohil 3 , Subhashish Bhattacharya 3 , Mark Juds 4 , Cheng Luo 4 , Randy Bowman 5 , Ronald Noebe 5 , Geraldo Nojima 4 , Kevin Byerly 1
1 , National Energy Tech Laboratory, Pittsburgh, Pennsylvania, United States, 2 Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States, 3 Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina, United States, 4 , Eaton Corporation, Menomenee Falls, Wisconsin, United States, 5 , NASA Glenn Research Center, Cleveland, Ohio, United States
Show AbstractThe emergence of commercial and near-commercial wide-bandgap based semiconductor devices is anticipated to have broad impacts on efficiencies, power densities, and maximum temperatures of operation for a range of power electronics based converters. In parallel, a number of societal trends are increasing the demand for advances in power electronics based converters including the increased penetration of distributed generation resources on the electric power system and electrification of the transportation system amongst others. But the widespread deployment of advanced wide-bandgap based power converters will be limited by the availability of the balance of enabling technologies that are also required to operate under newly established operational envelopes of wide bandgap based semiconductor devices including the peripheral components and passives such as soft magnetics and dielectrics.
In this presentation, we will discuss recent advances and on-going project work in the area of soft magnetic nanocrystalline / amorphous nanocomposite alloys and their integration into core-level components for applications in a number of emerging wide-bandgap based power converters. State of the art properties in several existing and emerging classes of alloys will be reviewed, and recent developments in processing techniques and core-level, application relevant performance characterization will also be discussed. The potential for integration of advanced cores into new wide bandgap enabled power electronics converter topologies will also be presented along with advantages of the novel topologies such as 3-port power converters and variable frequency drives.
ES12.2: Soft Magnetic Materials for Next-Generation Power Electronics II
Session Chairs
Paul Ohodnicki
Mitra Taheri
Wednesday PM, April 19, 2017
PCC North, 200 Level, Room 227 C
2:30 PM - *ES12.2.01
Development of New Amorphous and Nanocrystalline Magnetic Materials for Use in Energy-Efficient Devices
Eric Theisen 1
1 , Metglas, Conway, South Carolina, United States
Show AbstractFe-based amorphous and nanocrystalline soft magnetic alloys have been intensively researched for many applications, including high efficiency electrical distribution and motor applications. New amorphous foils with a saturation magnetization of 1.64T and new nanocrystalline foils with saturation up to 1.85T have been developed. Often these new materials are not drop-in replacements for the conventional competing alloys and require significant changes in processing to be able to fabricate commercial devices.
The ductile amorphous foils are widely used in energy efficient transformers where the ribbon is cut to length and formed into a laced core. However, the nanocrystalline foils are mechanically too brittle to fabricate in the same way and a new processing method must be developed for use as a transformer core. We will also look at other applications, such as high efficiency motors, where the soft magnetic material properties are ideal but the challenges in fabrication limit the use of these new alloys.
3:00 PM - ES12.2.02
Tuning the High Frequency Behavior of a Nanocomposite Inductor
Dale Huber 1 , Grant Bleier 1 , Todd C. Monson 1 , John Watt 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractSuperparamagnetic nanoparticles are an ideal material for high frequency magnetic inductors due to their potential for high frequency response without hysteretic loses. We investigated the frequency dependent susceptibility of superparamagnetic nanocomposites as a function of particle size and interparticle spacing. As expected, nanoparticle size has a dramatic effect on the nanocomposite susceptibility, with smaller nanoparticles exhibiting improved high frequency susceptibility. The improved susceptibility at high frequency is partially compensated by lowered saturation magnetization due to lower loading of the magnetic material. Nanocoposites formed from iron and iron oxide nanoparticles were studied, and compared to more traditional materials based on metallic glasses and micron scale particulates. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
3:15 PM - ES12.2.04
Broadband Magnetic Behavior of Nano-Crystalline Alloys and Soft Ferrites
Enzo Ferrara 1 , Cinzia Beatrice 1 , Fausto Fiorillo 1 , Alessandro Magni 1 , Luca Martino 1 , Samuel Dobak 2 , Carlo Ragusa 3
1 Nanoscience and Materials, Istituto Nazionale di Ricerca Metrologica, Turin Italy, 2 Faculty of Science, P. J. Šafárik University, Institute of Physics, Košice Slovakia, 3 Energy Department, Politecnico di Torino , Turin Italy
Show AbstractAn overview is given of the broadband magnetic permeability and loss behavior of soft ferrites and nanocrystalline alloys with excellent high-frequency magnetic response, for applications in power electronics and telecommunication where increasingly high working frequencies f are required. To satisfy these requirements, sintered soft ferrites are used granting compromise between costs and physical properties. Superior broadband magnetic behavior is achieved with heat-treated nanocrystalline alloys, a smart alternative thanks to magnetic softness and reduced thickness. The nanocrystalline ribbons, also, are attractive because of the low cost of raw materials, higher saturation magnetization, and well-established preparation methods.
Assessing the loss and permeability features of these materials through the whole f range envisaged for applications is challenging as the magnetic characterization from DC to the GHz within an appropriate span of peak inductions requires a host of experimental solutions. Our results have been obtained combining fluxmetric measurements up to 10 MHz, partially overlapping with transmission line measurements, by which testing up to 1 GHz can be performed. Measurements are supplemented by the study of the domain wall DW dynamics by fast stroboscopic magneto-optical techniques. Besides, the assessment of losses over a many-decade f range stretches present-day theories, conceived for power frequencies. The basic concepts of loss separation still hold, although limitations in measurements and the analytical formulation are posed. E.g., measurements can consistently proceed up to the GHz and the theoretical approach be fully applied only under linear or quasi-linear constitutive magnetic equation, which implies low/very low measuring inductions (within the Rayleigh region). Interest is devoted in nanocrystalline alloys to the case when a transverse anisotropy is induced by field annealing in ribbons, which exhibit the highest permeability and lowest losses at all frequencies, up to 1 GHz. One can analytically predict their complex permeability and loss behaviors associated to rotational process, dominant beyond a few hundred kHz, by calculating a f dependent constitutive equation via the Landau-Lifshiz-Gilbert (LLG) model and introducing it in the electromagnetic diffusion equation. This leads to identify the contribution to loss and permeability by the DW motion and its subdivision in quasi-static and dynamic/excess parts. The LLG equation can so provide the onset for the high-f analysis of loss and complex permeability in soft ferrites. We account for the role of the internal/grain-to-grain demagnetizing fields and the distribution of amplitude and direction of the anisotropy fields. Yet, the rotational contribution to magnetization processes up to 1 GHz and the related dissipative effects are calculated, while the extra contribution by DW motion in the lower f range below 1 MHz is identified.
4:30 PM - *ES12.2.06
Novel Soft Magnetic Materials for Energy-Efficient Electric Motors
Josefina Silveyra 1 2 , Juan Manuel Conde Garrido 1 2 , Nicolas Di Luozzo 1 2 , Michael McHenry 3
1 , Universidad de Buenos Aires, Buenos Aires Argentina, 2 , CONICET, Buenos Aires Argentina, 3 , Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
Show AbstractFor the past decades amorphous and nanocomposite soft magnets have been a hot topic in the field of strategic materials based on their outstanding soft magnetic properties for a wide frequency-range. These materials successfully entered the market for low-frequency power transformers, high-frequency power electronics, magnetic shields, and sensor applications.
Because electric motors account for nearly half of global electricity consumption, advanced soft magnets capable of operating with low losses at high speeds have the potential to greatly provide energy-savings. But the adoption of these unconventional materials for electric motors requires advances in suitable and cost-efficient manufacturing processes.
In this work, we examine the role of soft magnetic materials in electric machines and discuss current materials’ limitations. Furthermore, we address iron loss modelling strategies. We review recent efforts and technological achievements of emerging amorphous and nanocomposite soft magnets in the high-efficient electric motors field.
5:00 PM - ES12.2.07
Nanoscale-Enabled Microinductors for Power Electronics
Eric Langlois 1 , Todd C. Monson 1 , Dale Huber 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractScaling and performance of magnetic passive components such as inductors and transformers has not kept pace with advances in high power semiconductor devices employing wide/ultra-wide band gap SiC, GaN, and AlN. These larger and heavier components limit the power density that can be achieved in power electronic systems. A new effort is needed to explore next generation mesoscale (i.e., mm size) magnetic passive components that go beyond the limits of current technology. Our proposed solution is to create inductors with reduced form factor and significantly lower energy losses using a novel nanoscale-enabled magnetic material that is nonconducting, non-hysteretic, and has a high saturation magnetization. This first-of-its-kind composite magnetic core material employs superparamagnetic iron nanoparticles embedded in an epoxy matrix. Other advantages afforded by this material are reduced heat generation and conduction to other circuit components as well as reduced air and sbustrate losses due to fringe fields. The new device will combine this nanocomposite material with microsytems technology developed at Sandia. This presentation will cover some intial computer modeling results showing our microinductor design parameter space, the performance impact of this novel nanocomposite material, and possible directions for future development activities.
5:15 PM - ES12.2.08
Amorphous Magnetic Thin Films and Their Integration in On-Chip Power Conversion Applications
Hao Wu 1 , Mahmoud Khdour 1 , Hongbin Yu 1
1 , Arizona State University, Tempe, Arizona, United States
Show AbstractIntegration of voltage regulator (VR) on the microelectronic chip substrate in system on chip (SoC) can reduce interconnect resistive losses, facilitate real-time power management with control of the supply voltage. [1-3] The main obstacle in miniaturizing VR is to manufacture small inductors with high inductance density, power density and efficiency with large current carrying capability. A number of processes were developed including planar spiral inductor, surface mount technology air-core inductors, integrated voltage regulators (IVR). Integration of magnetic material to on-chip inductors comes with challenges such as the compatibility issue with fabrication processes and maintaining high efficiency by suppressing eddy current losses. Current carrying capability can be increased by engineering the DC current-induced magnetic flux via the negative coupling of two inductors as demonstrated in.
In this research work we fabricated a strip-line on-chip inductor with separate conductive windings wrapped by boron-incorporated amorphous Co-4%Zr-4%Ta-8%B (at. %) film [4]. We examined its response of inductance and quality factor as a function of an applied DC current. Before the DC current was presented the inductor have an inductance of 3 nH, an increase from 0.4 nH of air core inductor without magnetic film. Introducing the DC current initially at small values does not change inductance value. Continued increase of the DC current leads to a reduction in inductance, this decrease can be attributed to the reduction of magnetization in the magnetic film in response to the magnetic field, HDC generated by the DC current in the inductor wire. Therefore, as DC current increases the magnetization decreases, which subsequently leads to a reduction in small signal inductance. The small signal inductance response at 300 MHz was extracted for all DC currents. Our strip-line inductor demonstrated a current carrying capability with a current density around 6 A/mm2 while maintaining ~ 100% inductance increase over the air-core inductance.
REFRENCES
[1] P. R. Morrow, C.-M. Park, H. W. Koertzen, and J. Dibene, "Design and Fabrication of On-Chip Coupled Inductors Integrated With Magnetic Material for Voltage Regulators," IEEE Transactions on Magnetics, vol. 47, pp. 1678-1686, 2011
[2] P. Herget, N. Wang, E. J. O'Sullivan, B. C. Webb, L. T. Romankiw, R. Fontana, et al., "A Study of Current Density Limits Due to Saturation in Thin Film Magnetic Inductors for On-Chip Power Conversion," IEEE Transactions on Magnetics, vol. 48, pp. 4119-4122, 2012.
[3] D. S. Gardner, G. Schrom, P. Hazucha, F. Paillet, T. Karnik, S. Borkar, et al., "Integrated On-Chip Inductors with Magnetic Films," in Electron Devices Meeting, 2006. IEDM '06. International, 2006, pp. 1-4.
[4] H. Wu, D. S. Gardner, W. Xu, and H. Yu, "Integrated RF On-Chip Inductors With Patterned Co-Zr-Ta-B Films," IEEE Transactions on Magnetics, vol. 48, pp. 4123-4126, 2012
ES12.3: Poster Session: Soft Magnetic Materials for Next-Generation Power Electronics
Session Chairs
Enzo Ferrara
Todd C. Monson
Thursday AM, April 20, 2017
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - ES12.3.01
Structural and Magnetic Properties of Co2MnAl Alloys Prepared by Mechanical Alloying
Chunghyo Lee 1 , Donghyeon Seo 1
1 , Mokpo National University, Muan-gun, Chonnam Korea (the Republic of)
Show AbstractA Heusler alloy is a ferromagnetic metal alloy based on a Heusler phase. Heusler phases are ternary intermetallics with stoichiometric composition X2YZ (X=Fe, Co, Ni, …, Y=V, Mn, …, Z=Al, Si, …) and face-centered cubic crystal structure. They have drawn considerable interest during the last century due to the possibility of studying different magnetic behavior such as antiferromagnetism, Pauli paramagnetism and half-metallic ferromagnetism in the same family of alloys. Among some kinds of Heusler phases, Co-based Heusler alloys are of particular interest due to comparatively high Curie temperatures. Mechanical alloying (MA) has been widely used for preparing numerous advanced engineering materials with unique properties and structures.
In the present work, the effect of mechanical alloying on the formation of a Co2MnAl Heusler alloy was investigated. α-(Co,Mn,Al) FCC phase coupled with amorphous phase were obtained by 5 hours of MA from a mixture of Co50Mn25Al25 powders without any evidence for the formation of Co2MnAl compound. On the other hand, a Co2MnAl Heusler compound could be formed by the heat treatment of MA powders up to 700°C. Magnetic measurements was also taken as one of the evidences for the formation of ferromagnetic Co2MnAl compound. Acknowledgements This work is financially supported by the Ministry of Knowledge Economy (MKE) of Korea.
9:00 PM - ES12.3.02
Novel Rapid-Quenched Soft Magnetic Amorphous Thin Film Materials Using High Glass Forming Elements for Ultra-Low Electrical Losses
Ansar Masood 1 , Karl Ackland 3 , Plamen Stamenov 3 , Paul McCloskey 1 2 , Cian Mathuna 1 2 , Santosh Kulkarni 1
1 , Tyndall National Institute, Cork Ireland, 3 , Trinity College, Dublin Ireland, 2 School of Electrical and Electronic Engineering, University College Cork, Cork Ireland
Show AbstractWith significant advances in power semiconductors in high-speed power switches, the requirement for efficient high-frequency magnetic components becomes imminent. The high-frequency operation of a switch-mode power converter, for example, means that the value of inductance required and hence the size of the magnetic component can be greatly reduced. Over the last decade, there has been a significant research focused on developing high flux density soft magnetic materials to replace existing bulky and low flux density ferrite based solutions. Excellent soft magnetic properties and high resistivity are the prerequisites for these materials for high-frequency applications (>100 kHz). Amorphous and nanocrystalline ribbon materials offer many advantageous magnetic properties i.e. low coercivity Hc, high Bsat, and relatively high resistivity. It is well understood that as the operating frequency (f) increases, the eddy-current loss (We ∝ f2) increases more sharply than the hysteresis loss (Wh ∝ f) and the total core energy loss becomes dominant by We at f > 100 kHz. However, the minimum available thickness (~20 µm) of commercially available amorphous ribbons and their consequent susceptibility to eddy current loss restricts their use to low-frequency applications. This constrains the potential benefit of using a high flux density material and high-frequency operation for device miniaturization. In our recent work, we demonstrated a post-processing approach to realize low loss soft magnetic thin films for high-frequency power applications [1].
To address the above-mentioned challenges, we present a rapid quenching approach to fabricate ultrathin soft magnetic tapes of amorphous metals with a novel alloy Co-Fe-B-Si-Nb system for high-frequency (>100 kHz) power applications. Additionally, the novel alloy system significantly reduces the material costs and eliminates the need for post-processing steps while improving high-frequency loss performance. The alloy composition includes large glass forming elements to produce amorphous tapes with a thickness of ~8 μm in the as-quenched state. Structural analysis of the as-quenched tapes was confirmed to be amorphous by x-ray diffraction. Further, the static and dynamic properties of ultra-thin tapes were measured by BH-loop tracer and a high-frequency power loss characterization system developed in-house. The in-plane hysteresis loop revealed very low coercivity (Hc= 10 A/m) in the as-quenched state. The materials loss performance was investigated in the frequency range of 100-500 KHz and showed high material’s performance as compared to the commercially available soft magnetic ribbons. Further details on magnetic characterizations and power circuit testing will be presented in the full paper.
1. Kulkarni, S., et al., Low Loss Magnetic Thin Films for Off-Line Power Conversion. Ieee Transactions on Magnetics, 2014. 50(4).
9:00 PM - ES12.3.03
Laser Annealing of AeroJet-Printed NiZn-Ferrite Films and Embedding into Plastic Substrate for Flexible Electronics
Rajaram Kaveti 1 , Jihoon Kim 1
1 , Kongju National University, Cheonan Korea (the Republic of)
Show AbstractThis work describes a novel process for preparing NiZn-Ferrite films by AeroJet dispenser printing process. This method allows precise additive fabrication of electronic components onto any substrate under ambient conditions. Uniform NiZn-Ferrite films were successfully printed without any cracks by controlling the ink-droplet size and ink-droplet pitch. The AeroJet-printed films were annealed by IR laser (808 nm) to improve their crystallinity and magnetic properties. The effect of laser power and beam diameter on the magnetic properties and the morphology of NiZn-ferrite film magnets were investigated. The laser-annealed NiZn-ferrite films were detached from the original rigid substrate by chemically dissolving a sacrificial layer in between the printed film and the substrate, then embedded into flexible polymeric substrates. Structural and magnetic properties of NiZn-ferrite films associated with their flexibility were investigated by scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and LCR-meter before and after a bending test. Our results contribute to the printing of magnetic passive components in future flexible integrated electronic systems.
9:00 PM - ES12.3.04
Studies on Magnetic Properties of Fe-N Nanopowder Prepared by Plasma Arc Discharge
Kiran Shinde 1 , M. Ranot 1 , H. Kim 2 , Jong-Woo Kim 1 , C. Choi 1 , K. Chung 1
1 Powder & Ceramic Division, Korea Institute of Material Science, Changwon Korea (the Republic of), 2 Superconductivity Research Centre, Korea Electrotechnology Research Institute, Changwon, Gyeongnam, Korea (the Republic of)
Show AbstractDuring the past decades, iron nitrides have received considerable scientific and technological attention due to their diverse phase structures and interesting magnetic properties. Iron nitride compounds are known to exist in varieties of phases having distinct crystal structure and magnetic properties. Among the different phases, the ferromagnetic iron nitride (α″-Fe16N2) with body centered tetragonal structure has been paid much attention as a new candidate for future permanent magnet material with rare earth free. It was reported that α″-Fe16N2 phase have saturation magnetization (Ms) is 240 emu/g and magnetocrystalline anisotropy constant (Ku), is about 1x107 erg/cm3 at room temperature.
Attempts to fabricate α″-Fe16N2 by using dc plasma arc discharge method have been employed in this work. Keeping the experimental conditions constant, ~10 kW power and ~4 kPa pressure of chamber filled with different compositions of nitrogen based gases, the synthesized Fe-N powders were analyzed structurally and morphologically by x-ray diffraction and scanning electron microscopy respectively. The Fe nanoparticles are spherical in shape having particle size in the range of 20-100 nm. The magnetic properties of fabricated nano-powders have been studied by PPMS and approach to fabricate the Fe16N2 phase will be discussed.
Symposium Organizers
Todd C. Monson, Sandia National Laboratories
Enzo Ferrara, Istituto Nazionale di Ricerca Metrologica
Mitra Taheri, Drexel University
Torbjorn Thiringer, Chalmers University of Technology
Symposium Support
U.S. Department of Energy-Office of Electricity Delivery and Energy Reliability
U.S. Department of Energy-Office of Electricity Delivery and Energy Reliability Energy Storage Program
Sandia National Laboratories
ES12.4: Soft Magnetic Materials for Next-Generation Power Electronics III
Session Chairs
Eric Langlois
Todd C. Monson
Thursday AM, April 20, 2017
PCC North, 200 Level, Room 227 C
10:30 AM - ES12.4.02
Mechanochemical Synthesis and Characterization of Nanocrystalline Iron Nitride
Baolong Zheng 1 , Yizhang Zhou 1 , Stanley Atcitty 2 , Enrique Lavernia 1 , Todd C. Monson 2
1 , University of California, Irvine, Irvine, California, United States, 2 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractNanocrystalline (NC) iron nitrides (FexNy) have magnetic moments well in excess of current state of the art soft magnetic materials. In this work, we report a novel synthesis approach to prepare NC γ’-Fe4N powder using a two-step process: The first-step is to use cryomilling to produce NC Fe powder with a high density of vacancies, grain boundaries, and dislocations. These defects can further serve as fast diffusion pathways for nitrogen atoms, through which the following nitriding of NC Fe powder is enhanced. The second-step is to nitride the NC Fe powders in NH3 environment at 300oC and 350oC for synthesis of NC γ’-Fe4N powder. The temperature required for nitridation was substantially reduced by means of nano-crystallization of Fe. Moreover, γ’-Fe4N is thermally metastable and fabrication of bulk FeN still remains a challenge. In the present study, the spark plasma sintering (SPS) is also explored to consolidate NC γ’-Fe4N powder into its bulk form. Electron microscopy, XRD and thermal-analysis are conducted to understand the microstructural evolution in the NC γ’-Fe4N. The grain refinement, phase transformations, as well as related thermodynamics are discussed to provide insight into fundamental phenomena in the synthesis of NC γ’-Fe4N.
10:45 AM - ES12.4.03
Scalable Synthesis and Fabrication of a Soft Magnetic Nanocomposite
John Watt 1 , Grant Bleier 1 , Todd C. Monson 1 , Dale Huber 1
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Show AbstractMagnetic nanocomposites are a new class of material that will allow for rational inductor design for power electronics. The composition, size, and interparticle spacing of the target nanoparticles can all be tuned to maximize performance for specific frequency and power requirements. Zero-valent iron nanoparticles are a promising candidate for inductor applications due to the emergence of the superparamagnetic phenomenon at small sizes. Such superparamagnetic nanoparticles possess zero magnetic coercivity and are too small to support eddy currents, thereby removing two of the largest sources of energy loss.
To ensure uniform switching and to prevent ferromagnetic domains from forming the size, shape and spacing of the nanoparticles within the nanocomposite must be closely controlled. We present a method that allows for the systematic growth of zero-valent iron nanoparticles with tight size and shape distribution via a reversible agglomeration method. This occurs by the thermal decomposition of continuously added iron precursor in an Extended LaMer mechanism.[1] We then demonstrate the scalability of this approach by synthesizing gram scale amounts of well-defined zero-valent iron nanoparticles.
The nanoparticles are then formed into a thermosetting magnetic nanocomposite. The nanocomposite has good workability enabling it to be cast into custom 3D printed molds. Upon curing we obtain a mechanically strong, magnetically active material which shows promise for the next generation of inductors for power electronics.
Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
[1] E. C. Vreeland, J. Watt, G. B. Schober, B. G. Hance, M. J. Austin, A. D. Price, B. D. Fellows, T. C. Monson, N. S. Hudak, L. Maldonado-Camargo, A. C. Bohorquez, C. Rinaldi, D. L. Huber, Chem. Mater. 2015, 27, 6059-6066.
11:30 AM - *ES12.4.04
Magnetic and Electrical Characterization of Nickel-Rich NiFe Thin Films and Nanotubes Synthesized by ALD
Juan Escrig 1
1 , Universidad de Santiago de Chile, Santiago Chile
Show AbstractNiFe alloys are ubiquitous in technology and famous for Permalloy, that is a ferromagnetic Ni81Fe19 alloy that exhibits unique magnetic properties such as high permeability, small coercivity, negligible magnetostriction, and distinct anisotropic magnetoresistance. It is used for the cores of tape recorder heads and in hard disk drive heads, in motor cases, and in magnetic resonance tomography shield covers. For future technologies, it serves as a model system to analyse the effects of nanostructuring on the symmetry and dynamics of domain walls [2]. Despite the fact, that already several techniques are available for growing NiFe films, such as, sputter deposition, electrodeposition, micromolding, and molecular beam epitaxial, to name a few of them, they exhibit specific drawbacks like step edge covering, need for a liquid electrolyte or ultra high vacuum. Therefore, we want to utilize atomic layer deposition (ALD) to synthesize NiFe thin films in a quality comparable to the established preparation methods but with the advantage of good uniformity even in shadowed areas, control of thickness due to the self-limiting growth behavior, better step coverage, and being a relatively low-cost technique [3]. Moreover, ALD provides the unique ability – compared to the standard physical and chemical vapour deposition techniques – to perfectly mold 3D, high-aspect ratio nanostructures without shadowing effects [3]. In an ALD process, the reactants are separately supplied into the reactor in a cyclic fashion. The non-overlapping alternate injection of the precursors prohibits the direct chemical reaction of the gases resulting in CVD in the gas phase and thus leads to a deposition that highly depends on adsorption and surface reaction kinetics [4]. The chemical reactions on the substrate’s surface within the ALD-half-cycles make ALD a self-limiting process inherently capable of achieving precise layer growth. In this work [1] we report the combination of supercyclic ALD with thermal reduction to synthesize NiFe thin films or nanotubes. In particular, we have investigated the crystallinity and morphology of the ALD-prepared thin film samples before and after the reduction process, and set them into the relation with respect to electrical and magnetic properties. Additionally, we have synthesized as a proof-of-concept Ni83Fe17 nanotubes with a composition close to Permalloy in an anodic alumina membrane and have measured the magnetic properties of an array and an isolated nanotube.
References
[1] A. P. Espejo, R. Zierold, J. Gooth, J. Dendooven, C. Detavernier, J. Escrig, K. Nielsch, Nanotechnology, 27, 345707, 2016.
[2] M. Klaui, J. Phys.: Condens. Matter, 20, 313001, 2008.
[3] R. L. Puurunen, J. Appl. Phys., 97, 121301, 2005.
[4] T. Suntola, M. Simpson, Atomic Layer Epitaxy (London: Blakie and Sons), 1990.
12:00 PM - ES12.4.05
Embedment of All-Inkjet-Printed Inductor/NiZn-Ferrite Structure into Plastic Substrate for Flexible Wireless Power Transfer Module
Murali Bissannagari 1 , Jihoon Kim 1
1 , Kongju National University, Cheonan-si Korea (the Republic of)
Show AbstractInkjet-printed NiZn-ferrite films were detached from rigid substrate after annealing at elevated temperatures with an aid of a sacrificial layer. A sacrificial layer was prepared onto the rigid substrate in order to minimize a intermixing at the interface between the inkjet-printed NiZn-ferrite film and the rigid substrate. The detached NiZn-ferrite films were embedded into flexible substrates such as polydimethylsiloxane (PDMS) or polyimide (PI). Structural and Magnetic properties of the embedded NiZn-ferrite films were investigated by various characterization techniques such as X-ray diffraction, Field-emission SEM, vibrating sample magnetometer (VSM), and impedance analyzer. In order to apply the embedded NiZn-ferrite films to wireless power transfer (WPT), Ag spiral inductor coil pattern was printed on the detached NiZn-ferrite film by inkjet printing before the embedding process. Flexibility of the embedded coil/NiZn-ferrite structure was investigated by a bending test. The crack propagation during the bending test was monitored by the change in the resistance of the inductor coil. The WPT performance was demonstrated by applying the embedded coil/NiZn-ferrite structure as a power receiving unit (Rx) with a commercial power transmitting unit (Tx). A series of LED lights were successfully turned on by the wireless power received by the flexible Rx unit.
12:15 PM - ES12.4.06
Dynamic Magnetic Properties of Ferrites Prepared by Sol-Gel Autocombustion Method
Marco Coisson 1 , Gabriele Barrera 1 , Federica Celegato 1 , Luca Martino 1 , Shashank Kane 2 , S Raghuvanshi 2 , Paola Tiberto 1 , Enzo Ferrara 1
1 , INRIM, Torino Italy, 2 School of Physics, Devi Ahilya University, Indore, MP, India
Show AbstractFerrites have been extensively studied in the last decades because of their high versatility, low cost, and ease of tailoring their magnetic properties. Therefore, they have found a variety of applications, especially in power, electronics and radiofrequency. Because of their widespread use, the quest for optimisation of their properties and for cost reduction is still extremely up to date.
Co-Zn, Ni-Zn and Mg-Zn ferrites (AxZn1-xFe2O4 with A = Co,Ni,Mg) have been prepared by sol-gel autocombustion method. This technique produces materials in powder form having crystallites size of a few tens of nanometers. The as-obtained powders already have good structural and magnetic properties that for most applications do not require further annealing, therefore allowing faster production and lower energy consumption. Samples of the three studied families have been obtained with variable content of the two substituting elements. X-ray diffraction has been extensively employed to investigate their microstructure and to assess the cation distribution as a function of the composition. Magnetic properties have been investigated either by static hysteresis loops measured with a vibrating sample magnetometer, and by dynamic hysteresis loops measured with a custom fluxmetric setup allowing the application of fixed-frequency (~ 70 kHz), high intensity (up to ~ 50 mT) magnetic fields. This setup is particularly useful because it allows the measurement of hysteresis losses in samples constituted by unsintered powders and undefined shape. Static and dynamic properties and hysteresis losses are compared and related to the microstructure of each sample.
As a function of the composition, in each family of samples, different magnetic properties arise from the cation distribution of (Co,Ni,Mg) and Zn that prefer different substitution sites (B-site for Co,Ni,Mg and A-site for Zn). The losses have been calculated from static hysteresis loops by multiplying loops areas by the frequency at which dynamic loops are measured, and by dividing by the sample mass, to make losses comparable in the two conditions. These ferrites, especially when prepared with methods different from the conventional ceramic one, present particularly high resistivity, making them attractive for high-frequency applications, where low losses and reduced temperature increase during operation are envisaged.
The structural and magnetic properties of the three different families of ferrites are compared and suitability for power applications is discussed.