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

Shi-Yu Liu^1*, Ye-Ren Chang¹, Zong-Yuan Lin¹, Yu-Jou Shih¹, Yu-Tso Liao¹, Po-Hsun Wu², Ssu-Yen Huang², Wen-Chin Lin¹, Fang-Yuh Lo¹

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

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

Several studies have revealed using rare earth (RE) elements instead of yttrium to regulate the strain-induced magnetic anisotropy of garnet films in recent years. In this study, we used pulsed laser deposition to fabricate RE iron garnet (REIG) thin films on (111)-oriented yttrium aluminum garnet (YAG) substrates. REIG films formed crystalline garnet films with a preferred (111)-orientation. Samarium iron garnet (SmIG) has a rather rough surface because of the larger lattice mismatch between SmIG and YAG substrates. Due to negative magnetostriction constant and out-of-plane compressive strain, SmIG and holmium iron garnet (HoIG) films show strong perpendicular magnetic anisotropy (PMA) in vibrating sample magnetometry and magneto-optical Faraday effect (MOFE). MOFE also revealed that the REIG films have different sensitivities at different wavelengths of light. Moreover, as the thickness of SmIG and yttrium iron garnet is reduced, the easy magnetic axis tilting toward the surface normal is observed. This indicates stronger PMA in thinner iron garnet thin films, which experience stronger strain from the substrate. Therefore, our findings could pave the way for high-density nano-scale magnetic information storage based on REIG thin films.

Keywords: Rare-earth, Perpendicular magnetic anisotropy, ferrimagnetism