Epitaxial growth and properties of metastable BiMnO3 thin films

Epitaxial thin films of BiMnO3 were deposited on single-crystal substrates of (100)-oriented SrTiO3 by pulsed-laser deposition. Structural analysis by x-ray diffraction, electron diffraction, and transmission electron microscopy (TEM) indicated that the films were monoclinic and twinned with two dominant orientation relationships. The first is (111) BiMnO3 parallel to (100) SrTiO3 and similar to[(1) over bar 01] BiMnO3 parallel to <010> SrTiO3; the second is (10(1) over bar) BiMnO3 parallel to (100) SrTiO3 and similar to[121] BiMnO3 parallel to <010> SrTiO3. High-resolution TEM images revealed that there is no reaction or appreciable interdiffusion at the substrate/film interface, despite the high temperature of the substrate during deposition (similar to1000 K). Magnetic characterization was carried out (both magnetization versus temperature and hysteresis loops) and the results agree with previous reports of a ferromagnetic transition with T(C)similar to105 K. The actual value of T-C in the films is a few degrees lower than the bulk material, the discrepancy being attributed to strain, nonstoichiometry, or size effects. (C) 2004 American Institute of Physics.