Authors:	Ding, Shilei Baldrati, Lorenzo Ross, Andrew Ren, Zengyao Wu, Rui Becker, Sven Yang, Jinbo Jakob, Gerhard Brataas, Arne Kläui, Mathias
Title:	Identifying the origin of the nonmonotonic thickness dependence of spin-orbit torque and interfacial Dzyaloshinskii-Moriya interaction in a ferrimagnetic insulator heterostructure
Online publication date:	4-Nov-2020
Year of first publication:	2020
Language:	english
Abstract:	Electrical manipulation of magnetism via spin-orbit torques (SOTs) promises efficient spintronic devices. In systems comprising magnetic insulators and heavy metals, SOTs have started to be investigated only recently, especially in systems with interfacial Dzyaloshinskii-Moriya interaction (iDMI). Here, we quantitatively study the SOT efficiency and iDMI in a series of gadolinium gallium garnet (GGG)/thulium iron garnet (TmIG)/platinum (Pt) heterostructures with varying TmIG and Pt thicknesses. We find that the nonmonotonic SOT efficiency as a function of the magnetic layer thickness is not consistent with the 1/thickness dependence expected from a simple interfacial SOT mechanism. Moreover, considering the insulating nature of TmIG, our results cannot be explained by the SOT mechanism established for metallic magnets where the transverse charge spin current can inject and dephase in the magnetic layers. Rather we can explain this nonmonotonic behavior by a model based on the interfacial spin mixing conductance that is affected by the thickness-dependent exchange splitting energy by determining the phase difference of the reflected spin-up and spin-down electrons at the TmIG/Pt interface. By studying the Pt thickness dependence, we find that the effective DMI for GGG/TmIG/Pt does not depend on the Pt thickness, which indicates that the GGG/TmIG interface is the source of the iDMI in this system. Our work demonstrates that SOT and DMI can originate from two different interfaces, which enables independent optimization of DMI and SOT for advanced chiral spintronics with low damping magnetic insulators.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-5265
Version:	Accepted version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	In Copyright
Information on rights of use:	https://rightsstatements.org/vocab/InC/1.0/
Journal:	Physical review : B 102 5
Pages or article number:	Art. 054425
Publisher:	APS
Publisher place:	Ridge, NY
Issue date:	2020
ISSN:	2469-9950
Publisher URL:	https://doi.org/10.1103/PhysRevB.102.054425
Publisher DOI:	10.1103/PhysRevB.102.054425
Appears in collections:	JGU-Publikationen