Epitaxial magnetic garnet thin films and heterostructures by pulsed laser deposition

Epitaxial yttrium-iron-garnet (YIG) films, bismuth-iron-garnet (BIG) films, and YIG/BIG heterostructures have been grown on [111] oriented single crystalline gadolinium-gallium-garnet (GGG) substrates by pulsed laser deposition (PLD), using a KrF excimer laser system. The films under study were grown over a range of temperatures from 600 °C to 800 °C and at 100 mTorr oxygen partial pressure. The effects of oxygen partial pressure during cooling on the structure, composition and magnetic properties of the films were investigated, employing X-ray diffraction, Rutherford back scattering spectroscopy coupled with He ion channeling, and vibration sample magnetometry. All specimens under study indicated that, independent of the film-substrate mismatch, the grown films were single crystalline in the [111] orientation. Preliminary studies on the effects of cooling oxygen partial pressure on the film structure indicate an increase in lattice distortion in the direction normal to the film surface with decreasing pressure. The magnetic properties of the films are comparable to the YIG bulk properties, and all films indicated in plane preferential magnetization, independent of cooling conditions.