STUDIES OF MAGNETIC-INTERACTIONS BETWEEN GD GRANULES IN COPPER MATRIX

Ultrafine Gd particles in the Cu metallic material have been obtained by rapid annealing of sputtered metastable GdCu1-x alloys. The particle shape and size were measured by a transmission electron microscopy. The evolution of crystal structure with annealing temperature has been investigated by x-ray diffraction and electron diffraction. It has been found that the Gd granules have formed following annealing above 300-degrees-C and the granular size increases with rising annealing temperature. The magnetic data show that the as-sputtered metastable Gd0.1Cu0.9 and Gd0.2Cu0.8 alloys obey a Curie-Weiss law at high temperature with a negative value of theta. After annealing, the theta value varies with annealing temperature according to an oscillatory function. The evolution of the magnetic properties and microstructure during annealing are described in detail.