Observation Of Rotation Of Spin-Polarization With The Verwey Transition At A Surface Of A < 110 >-Oriented Magnetite Whisker By Field-Emitted Electron Polarimetry

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.