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

Liu, Xiaoran and Singh, Sobhit and Kirby, Brian J and Zhong, Zhichen and Cao, Yanwei and Pal, Banabir and Kareev, Mikhail and Middey, Srimanta and Freeland, John W and Shafer, Padraic and Arenholz, Elke and Vanderbilt, David and Chakhalian, Jak (2019) Emergent Magnetic State in (111)-Oriented Quasi-Two-Dimensional Spinel Oxides. In: NANO LETTERS, 19 (12). pp. 8381-8387.

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Abstract

We report on the emergent magnetic state of (111)-oriented CoCr2O4 ultrathin films sandwiched between Al2O3 spacer layers in a 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 measurements demonstrate the appearance of a long-range ferromagnetic ordering of spins on both Co and Cr sublattices. Brillouin function analyses and ab-initio density functional theory calculations further corroborate that the observed phenomena are due to the strongly altered magnetic frustration invoked by quantum confinement effects, manifested by the onset of a Yafet-Kittel-type ordering as the magnetic ground state in the ultrathin limit, which is unattainable in the bulk.

Item Type:	Journal Article
Publication:	NANO LETTERS
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright of this article belongs to AMER CHEMICAL SOC
Keywords:	Spinels; ultrathin films; emergent properties; magnetism
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	06 Jan 2020 09:19
Last Modified:	06 Jan 2020 09:19
URI:	http://eprints.iisc.ac.in/id/eprint/64296

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