Magnetooptical Study Of The Growth-induced Uniaxial Anisotropy Of

Abstract

For the experiments we used garnet films of composition (BiLuh(FeGa)S012 grown on (GdCa}J(GaMgZr)sOI2 and Gd3GaS0 1 2 substrates. Deviation of the crystallographic axis {21O} from the the film normal was less than 1°. Domain nucleation fields (Hp,Hn)nuc (H p is the in-plane field, Hn is the perpendicular one), were measured for different azimuthal angle cj> of Hp relative to the {120} axis by observation of the jump of the magnetization from the magneti cally saturated state. From the dependence of Hn on Hp for different cj> (Fig. 1), we have deter mined the easy axis (EA). From the comparison of these results with data from X-ray measure ments we have found that the EA of the samples investigated is situated close to the (001) plane and inclined from film normal n at an angle eo towards the {120} axis (Fig. 2.) The values of eo calcula � d from the susceptibility ratio XnnlXnp = tan eo (evaluated for cj> = 0, i.e. Hp is directed along {I20} ) are 9°, 20°,29°, and 30° for different samples.For fields Hn > 41tMs, which support the saturated state with critical field Hp in accordance with Stoner-Wohlfarth theory, nucleation takes place by nonreversible rotation of Ms. For cj> == ±TCI2, two directions of rotation are possible. The threshold values Hn and Hp depend on the uniaxial anisotropy field. 60 40 20 'V III 0 0