4:45 PM - EL03.10.10
Electric Field Control of Magnetism in Double Perovskites Coupled with Bismuth Ferrite
Vishal Ravi1,Bhagwati Prasad1,Yen-Lin Huang1,Jose Flores2,Fengyuan Yang2,Ramamoorthy Ramesh1
University of California, Berkeley1,The Ohio State University2
Multiferroic materials offer exciting pathways to manipulate both magnetic and electronic properties simultaneously, which, in the case of bismuth ferrite, stem from the intrinsic linking of ferroelectric and antiferromagnetic degrees of freedom. By leveraging this fundamental coupling, we can modify and indeed switch the ferromagnetism of materials such as Co0.9Fe0.1 that sit adjacent to ferroelectric bismuth ferrite thin films, using only electric fields . Using an oxide ferromagnet instead, such as La0.7Sr0.3MnO3, could potentially confer on these devices an improved fatigue life, as oxidation may be less critical .
This electric field control of magnetism through magnetic coupling opens up a vast array of applications, particularly in logic, data, and spintronics, where we may manipulate magnetic memories such as magnetic tunnel junctions with the application of an electric field, instead of through more energy-intensive spin-transfer torque currents .
Double perovskites, such as Sr2FeMoO6 (SFMO) and Sr2CrReO6 (SCRO), are promising candidates for ferromagnets that may provide such coupling with bismuth ferrite. As half-metallic oxides with Curie points higher than room temperature, both materials exhibit spin-polarised currents and potential perpendicular magnetic anisotropy, which are desirable for magnetic tunnel junctions and other magnetoresistance-based devices . Additionally, as these films are oxides rather than pure metals, they could provide an interface that is more robust against oxidation, leading to longer fatigue life.
We show the enhancement of these double perovskites’ coercive fields atop bismuth ferrite when compared to their isolated phases, which could uncover clues as to the strength of any magnetic coupling at the interface. We also explore magnetoelectric coupling by studying the effects of electric fields on the magnetisation of these double perovskites on bismuth ferrite, through giant magnetoresistance and anisotropic magnetoresistance measurements, in addition to correlated magnetic force microscopy and piezoresponse force microscopy images. These materials could lead to the next generation of low-power data storage and logic device technology.
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