Magnetic behaviour in Dy1 − xMmxCo2 compounds
The magnetic behaviour in Dy1 − xMmxCo2 (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5; Mm = mischmetal) compounds is reported using temperature and field dependence of magnetization (M–T and M–H respectively) measurements. A strong composition dependent irreversibility is observed in both the M–T and M–H scans below the magnetic ordering temperature (TC). A clear change of the first-order magnetic transition of DyCo2 to a second-order one in Dy0.5Mm0.5Co2 is evidenced by M–T and a series of Arrott (M2 versus H/M) plots, obtained from the M–H isotherms around TC. The variation in induced moments of the Co sublattice is estimated. It is found that the Mm substitution can only lead to a considerable reduction in the TC, saturation magnetization, and Co moment. The observed behaviour of M–T and M–H plots with increasing Mm content is discussed in detail.
Magnetic properties of Ho1−xMmxCo2 (x=0, 0.1, 0.2, 0.3 and 0.4) alloys and their hydrides
Abstract The influence of Mm (Mm=mischmetal) substitution and hydrogen absorption on the magnetic properties of Ho1−xMmxCo2 (x=0, 0.1, 0.2, 0.3 and 0.4) alloys have been determined through the temperature dependence of ac susceptibility and thermopower measurements. The changes in magnetic-ordering temperature of Ho1−xMmxCo2 alloys have been explained based on the dilution of the magnetic ions and weakening of 4f–3d exchange interactions. The gradual disappearance of the magnetic transition temperature upon increasing hydrogen concentration (y) has been interpreted by the lattice expansion and charge transfer between absorbed hydrogen and 3d-band of Ho1−xMmxCo2.
Changeover in the order of the magnetic phase transition in the intermetallic compounds (Er1-xTbx)Co2
Abstract Electrical resistivity, magnetization and AC susceptibility measurements have been carried out to investigate the order of the magnetic phase transition in (Er 1− x Tb x )Co 2 compounds. In this system a changeover from first- to second-order transition at about x c =0.60 was observed. This result is discussed in the framework of the generalized Inoue-Shimizu phenomenological model. Moreover, a microscope explanation about the order of the phase transition in terms of spin fluctuation and metamagnetism of the Co-3d subsystem is offered.