ناهمسانگردی چهتی مغناطوتنگش وگذارفاز مغناطیسی درمحلول جامدNd14 Dy2 Fe78 B6

  In this research. The magnetic phase transition and anisotropic magnetoelastic effects of a polycrystalline sample of Nd14Dy2Fe78B6 were studied by susceptibility and magnetostriction measurements. The composition was prepared by casting method. SEM pictures and XRD analysis showed that it was composed of polycrystalline magnetic phases with the main phase of 2-14-1. Results of ac susceptibility measurements show that the sample undergoes a magnetic phase transition at about 130 K, which is due to a gradual spin reorientaion accompanied with crystal structure distortion. Magnetostriction measurements in three orthogonal directions of the main body of the sample were performed in the range of 77 K to 300 K and in the field up to 1.5 T. At temperatures below 125 K, the magnetostriction values in three orthogonal directions differ by a factor of two to three. This anisotropy in magnetostriction indicates preferential orientation of the crystalline grains in the volume of the sample. In addition, magnetostriction curves show minimum values near the phase transition temperature with different values in the different directions. Minimum values of magnetostriction can be explained by the critical behavior of the orbital magnetic moments of the Fe atoms at the phase transition temperature.