Growth Induced Magnetic Anisotropy of Co-Substituted LPE Magnetic Garnet Films

The authors succeed in quantitatively explaining the uniaxial magnetic anisotropy of Co-substituted liquid-phase epitaxy (LPE) garnet films with an a-site Co²⁺ nonuniform distribution model. They also demonstrate that this anisotropy is induced by irregular Co²⁺ distribution during the growth process. A-site Co²⁺ makes a positive contribution to K1 and a negative one to K2, while d-site Co²⁺ makes a negative contribution to K1 and has no effect on K2. Using ferromagnetic resonance (FMR) to determine the crystalline anisotropy constants K1 and K2, and the uniaxial anisotropy constants KU, the authors determined that a-site Co²⁺ makes a dominant contribution. A-site can be further divided into four ai -sites. When Co²⁺ is evenly distributed to each of these ai -sites, then Co²⁺ contributes to K1 and K2, but while unevenly distributed at a single ai -site, it induces positive KU. When Co²⁺ is found at every ai -site, KU decreases and K1 increases. The predicted values were supported by experimental results.