EPITAXIAL YTTRIUM-IRON-GARNET FILMS GROWN BY PULSED-LASER DEPOSITION

Epitaxial Y3Fe5O12 (YIG) films have been grown by the pulsed laser deposition (PLD) technique on (111) gadolinium gallium garnet substrates. The effect of substrate temperature and oxygen partial pressure on the structure, composition, and magnetic properties of the films was investigated and compared to liquid phase epitaxy YIG films. The results demonstrated that epitaxial YIG films could be prepared under a wide range of deposition conditions, but narrow linewidth (DELTAH congruent-to 1 Oe) films were producible only at low oxygen partial pressures (O2 < 250 mTorr) and relatively high substrate temperatures (T(S) > 800-degrees-C). Since the linewidth of single-crystal YIG is dominated by surface and volume defects and/or impurities, the narrow linewidth indicated that PLD is a viable technique for producing high-quality ferrite films for microwave device applications. In addition, under all deposition conditions (50-1000 mTorr and 700-850-degrees-C) there is a uniaxial axis perpendicular to the film plane. However, at low oxygen pressure the uniaxial anisotropy energy constant K(u) is negative while at high oxygen pressure K(u) is positive.