Substrate induced magnetic anisotropies and magneto-optical response in YIG nanosized epitaxial films on NdGG(111)

Nanosized Y3Fe5O12 epitaxial films have been grown on Nd3Ga5O12 substrates using laser molecular beam epitaxy method. Magneto-optical polar Kerr effect, ferromagnetic resonance and spin wave propagation measurements show that the stress-related anisotropy field has an opposite sign, compared to that in the YIG/GGG systems. This leads to a considerable decrease of the effective magnetization that opens a perspective to get YIG films with perpendicular magnetization for utilizing forward volume spin waves. Longitudinal magnetooptical Kerr effect magnetometry reveals a large contribution of quadratic in magnetization terms into dielectric permittivity tensor at optical frequencies. This effect strongly increases with temperature decrease and is explained by magnetization of the interface Nd3+ ions that are exchange coupled to the Fe3+ ions.