Observation of Rotation of Spin-Polarization with the Verwey Transition at a Surface of a <110>-Oriented Magnetite Whisker by Field-Emitted Electron Polarimetry

Abstract

We observed the Verwey transition, i. e., metal-insulator transition, in a spin-polarization of field-emitted electrons from a topmost surface of a <110>-oriented magnetite whisker by means of field-emitted electron polarimetry. With a rise in temperature of the whisker to about 120 K, the polarization of field-emitted electrons increased from 4 to 11% with a rotation of its direction. The rotation angle corresponds to a change of magnetic easy axis from <001> to <111> direction caused by the Verwey transition. This result reveals that the Verwey transition occurs even at a surface as well as in a bulk. [DOI: 10.1380/ejssnt.2011.322]