Stress-Induced Perpendicular Magnetization in Epitaxial Iron Garnet Thin Films

• Published in: Applied physics express 2012-10, Vol.5 (10), p.103002-103002-3
• Main Authors: Kubota, Masashi, Tsukazaki, Atsushi, Kagawa, Fumitaka, Shibuya, Keisuke, Tokunaga, Yusuke, Kawasaki, Masashi, Tokura, Yoshinori
• Format: Article
• Language: English
• ISSN: 1882-0778; 1882-0786
• DOI: 10.1143/APEX.5.103002

We have grown pseudomorphic Tm 3 Fe 5 O 12 films (46--350 nm in thickness) with perpendicular magnetization on (111) Gd 3 Ga 5 O 12 substrates. Among various garnets, Tm 3 Fe 5 O 12 is selected because of a negatively large magnetostriction constant to overcome strong shape anisotropy in very thin films. A stress-induced anisotropy field as large as +25 kOe is estimated by calculation under a moderate in-plane tensile strain of +0.49%. The magnetization hysteresis loop and magnetic domain structure indicate the perpendicular easy axis. The domain size ($W$) in its maze pattern varies from 500 to 960 nm with increasing thickness ($t$) and agrees well with a scaling law of $W\propto\sqrt{t}$.