Single-crystal europium iron garnet (EuIG) thin films were epitaxially grown on gadolinium gallium garnet (GGG)(001) substrates using off-axis sputtering and showed strain-induced perpendicular magnetic anisotropy (PMA). By varying the sputtering conditions, we have tuned the europium/iron (Eu/Fe) composition ratios in the films to tailor the film strains. The films exhibited an extremely smooth, particle-free surface with a root-mean-square roughness as low as 0.1 nm, as observed by atomic force microscopy. High-resolution x-ray diffraction analysis and reciprocal space maps showed pseudomorphic film growth, a very smooth film/substrate interface, excellent film crystallinity with a rocking curve of 0.012° (ω scans), and an in-plane compressive strain without relaxation. In addition, spherical aberration-corrected scanning transmission electron microscopy showed an atomically abrupt interface between the EuIG film and GGG. The saturation magnetization $\left(M_s\right)$ and coercive field $\left(H_c\right)$ were measured using a vibrating sample magnetometer. The square-shaped out-of-plane M-H loops in conjunction with angle-dependent x-ray magnetic dichroism demonstrated the PMA in the films. The spin Hall magnetoresistance on Pt/EuIG samples was measured to obtain the PMA field strength $\left(H_{\perp }\right)$, which increases from 4.21 to 18.87 kOe with the increasing Eu/Fe ratio and in-plane compressive strain. We also measured spin transport in the Pt/EuIG bilayer structure and directly obtained the real part of spin mixing conductance to be $3.48\times {10}^{14}{\mathrm{\Omega }}^{\text{–}1}{\mathrm{m}}^{\text{–}2}$. We demonstrated current-induced magnetization switching with a low critical switching current density of $3.5\times {10}^6\mathrm{A}/\mathrm{c}{\mathrm{m}}^2$, showing excellent potential for low-dissipation spintronic devices.

• Received 20 February 2022
• Accepted 13 May 2022

DOI:https://doi.org/10.1103/PhysRevMaterials.6.054412