Spin Hall magnetoresistance and the effect of post-annealing temperature in the MOD-grown HoIG

Abstract

We present the fabrication of ultrathin Ho3Fe5O12 (HoIG) films on 111-oriented-Gd3Ga5O12 (GGG) via the metal-organic decomposition (MOD) method followed by a sequence annealing process. We characterized the crystal structure, surface morphology, and magnetic properties to study the effect of annealing tem-perature on the quality of MOD-grown HoIG films. For temperatures higher than 800 degrees C, we observe the infiltration of Iron (Fe) from the HoIG film into the GGG substrate. In particular, the Fe-diffusion is sig-nificantly enhanced for a 1000 degrees C-annealed sample of which crystal structure and magnetic properties are also affected. For temperatures lower than 800 degrees C, on the other hand, the smooth surface and strong crystallinity cannot be guaranteed. This suggests that an annealing temperature of 800 degrees C is the optimal condition for the MOD-grown HoIG film. The quality of the sample is further confirmed by measuring the spin Hall magnetoresistance (SMR) of HoIG/Pt, in which we found the unconventional angular dependence and comparable spin mixing conductance similar to the previous reports in other single crystalline IGs.(c) 2023 Elsevier B.V. All rights reserved.