Exploring Interfacial Exchange Coupling and Sublattice Effect in Heavy Metal/Ferrimagnetic Insulator Heterostructures using Hall Measurements, X-Ray Magnetic Circular Dichroism, and Neutron Reflectometry

Published

March 4, 2019

Author(s)

Qiming Shao, Alexander Grutter, Yawen Liu, Guoqiang Yu, Chao-Yao Yang, Dustin A. Gilbert, Elke Arenholz, Padraic Shafer, Xiaoyu Chi, Chi Tang, Mohammed Aldosary, Aryan Navabi, Qing Lin He, Brian Kirby, Jing Shi, Kang L. Wang

Abstract

Ferrimagnetic insulators (FMIs), such as rare-earth iron garnets, are of considerable interest for low-power spintronics due to low Gilbert damping and the absence of free charge carriers. FMIs are also promising candidate materials for high-frequency spintronic applications due to the antiferromagnetic exchange coupling between the two main sublattices. In addition, they allow time-reversal symmetry breaking in adjacent functional materials through interfacial exchange coupling without introducing disorder and current shunting. However, the interfacial exchange coupling and sublattice effects are difficult to characterize electronically due to the insulating nature of FMIs. Here, we use anomalous Hall effect (AHE) in a heavy metal/FMI bilayer to detect the onset temperature (T_M) of the FMI, which provide essential information regarding the interfacial exchange coupling and sublattice effects. The effects manifest as two types of sign change in AHE at varying temperatures. The first type originates in the dominance of the MPE at low temperature, which is confirmed by X-ray magnetic circular dichroism and polarized neutron reflectometry. The maximum AHE magnitude indicates the onset temperature of MPE, which increases with the FMI thickness. The second type occurs at T_M manifested as a sharp sign change accompanied by a divergent coercive field. Our results demonstrate that the AHE can provide an electrical probe for interfacial exchange coupling and sublattice effects in FMI-based spintronic devices.

Citation

Physical Review B

Volume

99

Issue

10

Pub Type

Journals

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Keywords

Magnetic insulator, Anomalous hall effect, Ferrimagnet, Thin film, Spintronic

Citation

Shao, Q. , Grutter, A. , Liu, Y. , Yu, G. , Yang, C. , Gilbert, D. , Arenholz, E. , Shafer, P. , Chi, X. , Tang, C. , Aldosary, M. , Navabi, A. , He, Q. , Kirby, B. , Shi, J. and Wang, K. (2019), Exploring Interfacial Exchange Coupling and Sublattice Effect in Heavy Metal/Ferrimagnetic Insulator Heterostructures using Hall Measurements, X-Ray Magnetic Circular Dichroism, and Neutron Reflectometry, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926433 (Accessed April 20, 2024)