Anomalous magnetic ordering in b-axis-oriented orthorhombic HoMnO3 thin films

Abstract

Orthorhombic HoMnO3 films with well-aligned crystallographic orientations were deposited on LaAlO3(110) single crystal substrates by using pulsed laser deposition. The nearly perfect b-axis-oriented films provide the opportunity of investigating the orientation-dependent physical property of this material. The temperature dependent magnetization evidently displays an antiferromagnetic ordering near 42K, irrespective to the direction of applied field. Furthermore, the theoretically expected lock-in transition was clearly observed at around 30K when field was applied along the c axis and was undetectable along the a and b axes. The 30K transition was suppressed to 26K when the applied field increased from 100to500Oe.