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Emergent Magnetic State in (111)-Oriented Quasi-Two-Dimensional Spinel Oxides



Xiaoran Liu, Sobhit Singh, Brian Kirby, Zhicheng Zhong, Yanwei Cao, Banabir Pal, Mikhail Kareev, Srimanta Middey, John W. Freeland, Padraic Shafer, Elke Arenholz, David Vanderbilt, Jak Chakhalian


We report on the emergent magnetic state of (111)-oriented CoCr2O4 ultrathin films sandwiched by Al2O3 in the quantum confined geometry. At the two-dimensional crossover, polarized neutron reflectometry reveals an anomalous enhancement of the total magnetization compared to the bulk value. Synchrotron x-ray magnetic circular dichroism (XMCD) demonstrates the appearance of long-range ferromagnetic ordering of spins on both Co and Cr sublattices. Brillouin function analyses further corroborates that the observed phenomena are due to the strongly altered magnetic frustration, manifested by the onset of a Yafet-Kittel type ordering as the new ground state in the ultrathin limit, which is unattainable in the bulk.
Nano Letters


Oxide magnetism, neutron scattering, x-ray scattering


Liu, X. , Singh, S. , Kirby, B. , Zhong, Z. , Cao, Y. , Pal, B. , Kareev, M. , Middey, S. , Freeland, J. , Shafer, P. , Arenholz, E. , Vanderbilt, D. and Chakhalian, J. (2019), Emergent Magnetic State in (111)-Oriented Quasi-Two-Dimensional Spinel Oxides, Nano Letters, [online], (Accessed April 23, 2024)
Created December 10, 2019, Updated October 12, 2021