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

• Published in: Journal of alloys and compounds 2023-04, Vol.941, p.169019, Article 169019
• Main Authors: Cao Van, Phuoc, Kim, Hyeongyu, Nguyen Thi, Trinh, Duong Viet, Duc, Cao, Viet Anh, Nah, Junhyo, Park, Sang J., Jin, Hyungyu, Jo, Younghun, Park, Seung-Young, Park, Jungjae, Yuk, Jong Min, Kim, Kab-Jin, Jeong, Jong-Ryul
• Format: Article
• Language: English
• Subjects: Annealing temperature; Holmium iron garnet; Magnetization compensation temperature; Metal-organic decomposition; Spin Hall magnetoresistance
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.169019

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 temperature on the quality of MOD-grown HoIG films. For temperatures higher than 800 ⁰C, we observe the infiltration of Iron (Fe) from the HoIG film into the GGG substrate. In particular, the Fe-diffusion is significantly enhanced for a 1000 ⁰C-annealed sample of which crystal structure and magnetic properties are also affected. For temperatures lower than 800 ⁰C, on the other hand, the smooth surface and strong crystallinity cannot be guaranteed. This suggests that an annealing temperature of 800 ⁰C 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. •Epitaxial HoIG thin films with ultra smooth surfaces (Ra = 0.088 nm) and high crystallinity is obtained via MOD method.•The annealing temperature strongly influences the Fe-diffusion from the HoIG film to the GGG substrate.•Compensation characteristic of HoIG film has been destroyed as the annealing temperature is too high.•Canted magnetic moment’s structure near the compensation temperature has been confirmed by angular dependence SMR signal.