Orthorhombic Magnetic Anisotropy in (EuBi)3Fe5O12 Garnet (110) Films

It was found that a large orthorhombic anisotropy is induced in (EuBi)3Fe5O12 garnet films grown on (110) NdGG substrates. The Bi content is controlled by regulating the melt composition and the supercooling temperature. Gyorgy´s parameter B = ¿2(Ku + Kp) increases linearly with the Bi content. The main part of B was found to be growth-induced. Gyorgy´s parameter A = Kp - Ku is very small and almost independent of the Bi content. The growth- and stress-induced parts of A were found to be considerably larger, but of opposite sign, and were found to compensate each other almost completely, although their respective absolute values increased with increasing Bi content. The following were obtained as the magnetic properties of the (Eu1·8 Bi1·2)3Fe5O12 film: saturation magnetization 4¿Ms = 1560 G, uniaxial anisotropy Ku = 1.6 × 10⁵ erg/cm³, in-plane anisotropy Kp = 1.6 × 10⁵ erg/cm³, quality factor Q = 1.7, material length l = 0.06 ¿m and wall mobility ¿w ¿¿o = 19 ms^¿1Oe^¿1. Such film might be useful as 0.5-¿m bubble material for current access devices.