Static magnetic proximity effects and spin Hall magnetoresistance in Pt/Y3Fe5O12 and inverted

Abstract

The magnetic state of heavy metal Pt thin films in proximity to the ferrimagnetic insulator Y 3 Fe 5 O 12 has been investigated systematically by means of x-ray magnetic circular dichroism and x-ray resonant magnetic reflectivity measurements combined with angle-dependent magnetotransport studies. To reveal intermixing effects as the possible cause for induced magnetic moments in Pt, we compare thin film heterostructures with different orders of the layer stacking and different interface properties. For standard Pt layers on Y 3 Fe 5 O 12 thin films, we do not detect any static magnetic polarization in Pt. These samples show an angle-dependent magnetoresistance behavior, which is consistent with the established spin Hall magnetoresistance. In contrast, for the inverted layer sequence, Y 3 Fe 5 O 12 thin films grown on Pt layers, Pt displays a finite induced magnetic moment comparable to that of all-metallic Pt/Fe bilayers. This magnetic moment is found to originate from finite intermixing at the Y 3 Fe 5 O 12 /Pt interface. As a consequence, we found a complex angle-dependent magnetoresistance indicating a superposition of the spin Hall and the anisotropic magnetoresistance in these types of samples. Both effects can be disentangled from each other due to their different angle dependence and their characteristic temperature evolution.

Quantitative comparison of the magnetic proximity effect in Pt detected by XRMR and XMCD

“…For samples with very high interfacial roughness or nonconducting FMs, where no MPE is expected and its presence is caused by interdiffusion due to the sample preparation, the differences in the quantitative results seem to get larger as found for the inverted Y 3 Fe 5 O 12 /Pt structure. 44 This could be caused by the change of the atomic surrounding of Pt, limiting the applicability of the calculated ab initio conversion factor or sum rule analysis, or other factors, which cannot be described by at least one of the two techniques without further investigations.…”

Quantitative comparison of the magnetic proximity effect in Pt detected by XRMR and XMCD

“…Being the first comparison of this kind, we can only call for further such multi-modal studies of interfacial magnetism, both for systematic quantitative checks of consistency between XRMR and XMCD as well as for the inherent complementarity of these two probes. For samples with very high interfacial roughness or non conducting FMs, where no MPE is expected, and its presence is caused by interdiffusion due to the sample preparation, the differences in the quantitative results seem to get larger as found for the inverted Y 3 Fe 5 O 12 /Pt structure 43 . This could be caused by the change of the atomic surrounding of the Pt, limiting the applicability of the calculated ab inito conversion factor or sum-rule analysis, or other factors which cannot be described by at least one of the two techniques without further investigations.…”

All-electrical Magnon Transport Experiments in Magnetically Ordered Insulators

“…In addition, the α-Fe 2 O 3 remains in the easy-plane magnetic anisotropy at all investigated temperatures, providing a large parameter space to conduct experiments. Since in the AFI the Néel-vector n orients perpendicular to the external magnetic field 63,70,[142][143][144][145][146][147][148][149] , SHE induced magnon transport is possible if the external magnetic field is aligned in-plane along the NM strips. To analyze the magnetic field dependence of the magnon transport signal at the detector, measurements in both in-plane field geometries, parallel and perpendicular to the strips, are necessary to remove additional weak background signals.…”