Nth. Kim-ngan et al., The surface insulator-metallic phase transition of epitaxial magnetite thin film observed by low-energy ion scattering, NUCL INST B, 164, 2000, pp. 992-998
The (1 1 1) surface of the magnetite thin film has been investigated by low
-energy ion scattering (LEIS) in the small-angle geometry and in the temper
ature range 85-300 K. The thin film has been grown by molecular beam epitax
y (MBE) and characterized by low-energy electron diffraction (LEED), scanni
ng tunneling microscopy (STM) and conversion electron Mossbauer spectroscop
y (CEMS). The temperature dependence of the scattered ion yield, R+(T), obt
ained by LEIS technique has shown anomaly around 120 K attributed to the in
sulator-metallic phase transition of this material. The character of the R(T) curve has been found to depend on the velocity of incoming ions. The re
sonant and Auger neutralization, which depends on the density of state and
on the degree of electron localization, can be responsible for the behavior
of the R+(T) curve, especially in the phase transition region. (C) 2000 El
sevier Science B.V. All rights reserved.