Room-temperature ground magnetic state of ε-Fe 2O 3: In-field Mössbauer spectroscopy evidence for collinear ferrimagnet

Abstract

ε-Fe 2O 3 is a remarkable iron(III) oxide polymorph exhibiting a large room-temperature (RT) coercive field, coupled magnetoelectric properties, and millimeter-wave ferromagnetic resonance. Despite great application potential, its room-temperature ground magnetic state is still under scrutiny. Employing in-field 57Fe Mössbauer spectroscopy, we unambiguously demonstrate that at room temperature, ε-Fe 2O 3 behaves as a collinear ferrimagnet, hence excluding any canting of sublattice magnetizations. When exposed to an external magnetic field, ε-Fe 2O 3 can be modeled as a two-sublattice ferrimagnetic nanomaterial with the highest coercivity among all currently known ferrimagnetic (nano)materials. © 2011 American Institute of Physics.