Verwey transition in field-emitted electrons from single <110>-oriented magnetite whisker

摘要

The authors investigated the Verwey transition in field-emitted electrons from a (HO)-oriented magnetite whisker by means of temperature and emission-current-controlled spin-polarization measurements. Under a condition of total emission current of 1.5 nA, which is relatively high within the measured range, the spin polarization began to increase around 100 K due to the Verwey transition. At the low-temperature region, the spin polarization was sensitive to the emission current and the energy. Therefore, it is suggested that t_(2g) band of Fe_3O_4 at the surface becomes narrower and possesses lower energy than that in an ideal bulky condition.