4 figures.We have studied an alloy of composition Ni51Mn28Ga21 prepared by rapid quenching in the form of a ribbon, with transformation temperature TM=337 K below the magnetic-order temperature, TC=344 K. Annealing of the samples was performed at 600 K for different times. From magnetic characterization a clear increase of the saturation magnetization accompanied with an increase of TC (up to 20 K) and TM (about 10 K) has been observed. XMCD measurements of both as-quenched and annealed samples have revealed great changes for the Mn and also the existence of a strong Ni signal. These results point out a possible non-negligible role of Ni, through the polarization of the conduction band, into driving the interplay between annealing and the magnetic properties in these materials.Peer reviewe
