Growth and characterization of Bi, Pr- and Bi, Sc-substituted lutetium iron garnet films with planar magnetization for magneto-optic visualization

The series of epitaxial garnet films of general composition Lu 3- x - y Bi x Pr y Fe 5- z Al z O 12 and Lu 3- x Bi x Fe 5- y - z Sc y Al z O 12 were grown on (111) oriented GGG (gadolinium gallium garnet) substrates by the liquid phase epitaxy. Their magnetic and magneto-optical properties were studied using both experimental techniques and modelling. All obtained films demonstrated generally a magnetic anisotropy close to the easy-plane type. The Pr-containing films exhibited large negative uniaxial anisotropy and significant cubic anisotropy. The latter causes a distortion of magnetization curves in samples magnetized in a direction normal to the film plane, especially at low temperatures. The large negative uniaxial anisotropy of Pr-substituted iron garnets allows us to increase the saturation field up to 0.5 T at liquid nitrogen temperature. The Sc-doped films displayed small positive uniaxial anisotropy that did not exceed the shape anisotropy. The magnetization curves of these films did not show any distortion due to the cubic anisotropy. The suitability of Pr- and Sc-doped garnets that meet the requirements for indicator layers for magneto-optic visualization at liquid nitrogen temperature is discussed.