The magnetization switching of CoNiO and CoCrPtTa thin films for longitudinal recording media on hard and flexible substrate, respectively, is studied by means of 3d magneto-optic Kerr effect vector magnetometry, which enables the determination of the evolution, of the magnetization vector, in orientation and modulus, during the variation of the applied field. The analyzed CoNiO films have both a single-layered and a triple-layered structure. The presence of a multilayered structure partly modifies the magnetization reversal towards a larger degree of coherence. The rotation of the magnetization results highly incoherent in CoCrPtTa. The magnetization is observed to go partly out of the film plane during the switching, which indicates the presence of an out-of-plane anisotropy. The comparison of the obtained results points out a different degree of incoherency of the magnetization switching in the different thickness CoCrPtTa films, which can be related to their different microstructure. (C) 2003 Elsevier Science B.V. All rights reserved.