Electronic structure and magnetic properties of transition metal diborides

The temperature dependencies of the magnetic susceptibility chi and its anisotropy Delta chi = chi - chi were measured for the hexagonal single crystalline TB2 compounds (T = Sc, Ti, Zr, Hf, V and Cr) in the temperature range 4.2-300 K. It was found that Delta chi varies strongly and nonmonotonously with the filling of the hybridized d-band, being almost temperature independent and the largest for the diborides of group 4 metals. Ab initio calculations of the electronic structure and susceptibility of the diborides provide evidence that magnetic anisotropy originates from competing Van Vleck paramagnetism and the orbital diamagnetism of conduction electrons. (C) 2009 Elsevier B.V. All rights reserved.