Strain-induced magnetic anisotropy of REIG thin films grown on YAG(111) substrates by pulsed laser deposition

Shi-Yu Liu^1*, Zong-Yuan Lin¹, Ye-Ren Chang¹, Yu-Tso Liao¹, Po-Hsun Wu², Ssu-Yen Huang², Fang-Yuh Lo¹

¹Physics, National Taiwan Normal University, Taipei, Taiwan
²Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Shi-Yu Liu, email:qwe957asd0801@gmail.com

In recent years, many research have proposed strain-induced anisotropy for ferrimagnetic insulator thin films to control their magnetic anisotropy. The magnetic anisotropy of garnet films can be varied by changing film thickness or substrates and substituting yttrium with rare-earth (RE) element. Therefore, we studied the RE iron garnet thin films on (111)-oriented yttrium aluminum garnet substrates by pulsed laser deposition. The structural properties and morphology of the RE iron garnet (REIG) films were measured by X-ray diffraction (XRD) and atomic force microscopy (AFM). The REIG films have a single-phase cubic garnet crystal structure, as confirmed by XRD, and the lattice parameter decreases as the ionic radius of RE elements decreases, while the crystallite size and strain increase. The surface roughness of REIG films from AFM measurement also decreases with decreasing ionic radius of RE metal ions. According to strain, iron garnet doped with samarium and holmium shows strong perpendicular magnetic anisotropy in vibrating sample magnetometer and magneto-optical Faraday effect. Moreover, saturation magnetization and Faraday rotation angle increase as the ionic radius of RE elements decreases. These results make a significant contribution to the study of magnetic anisotropy of ferrimagnetic insulators.

Keywords: ferrimagnetic insulator, magnetic anisotropy, strain