11:45 AM - *EL09.11.01
Hafnia-Based Ferroelectric Devices—A Singlular Type of Switching
Beatriz Noheda1,P. Nukala1,2,D. Carbone3,M. Ahmadi1,Y. Wei1,4,Sylvia Matzen5
University of Groningen1,Indian Institute of Science2,Lund University3,École Polytechnique Fédérale de Lausanne, EPFL4,University Paris-Saclay, CNRS5
Hafnia-based films are changing the way we think of ferroelectric switching. Ferroelectricity in these materials arises from metastable phases that are easier stabilized at the smallest dimensions. In addition they present low leakage as well as CMOS compatibility , making them ideal candidates for memory and logic devices. In addition, their switching takes place, quite uniquely, without involving domain wall motion, which allows experimental access to negative capacitance states. Multiferroic tunnel junctions (MTJs) fabricated with (La,Sr)MnO3 electrodes and ferroelectric Hf0.5Zr0.5O2 barriers show both tunneling magnetoresistance (TMR) and tunneling electroresistance effect (TER), displaying four resistance states by magnetic and electric field switching. Moreover, under electric field cycling, the TER effect can reach values as large as 106%. Experiments indicated that polarization switching alone cannot be responsible for those changes. In this talk we will show direct evidence, by means of operando transmission electron microscopy, as well as synchrotron x-ray diffraction experiments with in-situ application of electric fields, of the mechanisms that come into play during electric field switching in hafnia-based devices, as well as their relative importance determining the properties of these devices.
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 P. Nukala, G. Carbone, E. Stylianidis, R. Hamming Green, M. Salverda, Y. Wei, A. Burema, T. Banerjee , A. Bjorling, D. Mannix, S. Matzen, B. Noheda, (in preparation)