Surfaces of three selected materials were investigated by means of low--energy ion-scattering technique: (1) the magnetite (Fe 3 O 4 ) exhibiting the so-called Verwey transition (TV(bulk) = 125 K) accompanied by a small cubic-monoclinic crystal distortion, (2) the intermetallic compound NdMn2 undergoing an antiferromagnetic-paramagnetic phase transition (T N = 104 K) accompanied by a large crystal distortion with a volume change of 1%, and (3) the typical insulator BaTiO3 with two structural

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... nsitions below 300 K. The primary energy of the (Ne + , Ar + ) ion beam was in the range of 4-8 keV, and the low-energy ion-scattering spectra were collected in the temperature range of 85-300 K. A large influence from the Verwey transition on the neutralization and re-ionization of scattered ions from magnetite surface was observed, while no visible change at the magnetic phase transition in NdMn 2 was revealed in the low-energy ion-scattering spectra. A strong dependence of the characteristics of the low-energy ion-scattering spectra on the irradiated time was observed for BaTiO 3 indicating that this surface was heavily charged by ion bombardments.