Spin reorientation and first-order magpetisation process in HoFe11-xCoxTi compounds

The influence of Co substitution for Fe on the lattice parameters, ordering temperature, saturation magnetisation, spin-reorientation temperature, and first-order magnetisation process (FOMP) of HoFe11-xCoxTi (x = 0.3, 0.7, 1, 3, 5, 7, 9, 11) compounds is investigated. The tetragonal crystal structure of the parent HoFe11-xTi does not change upon Co substitution, but the lattice parameters a and c decrease monotonically with the increase of Co content. The increase of x in HoCoFe11-xCoxTi compounds has a beneficial effect in improving the Curie temperature from 513K in HoFe11Ti to 983 K in HoCo11Ti compound. The highest saturation magnetisation was observed in the compound with x = 3 at all measured temperatures. In HoFe11-xCoxTi compounds, with x = 0, 1, 3, 5, 7 a FOMP of type 11 occurs at fields less than 2T and below 100K. In HoFe2Co9Ti and HoCo11Ti compounds spin reorientations are observed at T-SR = 260 and 273 K, respectively. (C) 2007 Elsevier B.V. All rights reserved.