The magnetic structure of an epitaxial BiMn_(0.5)Fe_(0.5)O_3 thin film on SrTiO_3 (001) studied with neutron diffraction

摘要

High-angle neutron diffraction was used to directly reveal the atomic-scale magnetic structure of a single-crystalline BiMn_(0.5)Fe_(0.5)O_3 thin film deposited on a SrTiO_3 (001) substrate. The BiMn_(0.5) Fe_(0.5)O_3 phase exhibits distinctive magnetic properties that differentiate it from both parent compounds: BiFeO_3 and BiMnO_3. A transition to long-range G-type antiferromagnetism was observed below 120 K with a (111/222) propagation vector. A weak ferromagnetic behavior was measured at low temperature by superconducting quantum interference device (SQUID) magnetometry. There is no indication of the spin cycloid, known for BiFeO_3, in the BiMn_(0.5)Fe_(0.5)O_3 thin film. The neutron diffraction suggests a random distribution of Mn and Fe over perovskite B sites.