Solid phase epitaxy of ferrimagnetic Y3Fe5O12 garnet thin films

Abstract

Epitaxial Y3Fe5O12 thin films were grown on (111) Gd3Ga5O12 substrates by pulsed laser deposition and subsequent annealing above 1270 K. The as-grown films deposited at temperatures below 1070 K were amorphous and the absence of trivalent iron ions has been verified by electron spin resonance spectroscopy. The ex situ annealing above 1270 K in oxygen atmosphere converted the films into epitaxial ones with ferrimagnetic properties. The higher temperature annealing up to 1670 K enabled the higher TC and the shorter lattice constant approaching those of bulk, while the saturation magnetization stayed at 2μB/f.u. at 300 K. Slightly expanded lattice constants and reduced saturation magnetization values may originate from oxygen deficient crystal structures. Nonetheless, the epitaxial films preserved a fairly smooth surface with a root mean square roughness below 2 nm.