Effects of Cu substitution on structural and magnetic properties of La0.7Pr0.3Fe11.4Si1.6 compounds

The structure and magnetic properties of the La0.7Pr0.3Fe11.4−xCuxSi1.6 compounds have been investigated by X-ray diffraction, scanning electron microscopy and magnetisation measurements. Cu substitution for Fe in La0.7Pr0.3Fe11.4−xCuxSi1.6 (x = 0, 0.06, 0.12, 0.23, 0.34) leads to a reduction in hysteresis loss, a decrease in magnetic entropy change but an increase in Curie temperature (TC). The influences of annealing processes at different temperatures on TC, magnetic hysteresis, and the magnetocaloric effect (MCE) of La0.7Pr0.3Fe11.4Si1.6 are investigated in detail. It has been found that a short-time and high temperature annealing process has benefits for the formation of the NaZn13 types as phase compared to a long-time and low temperature annealing process.

► High temperature annealing process has benefits for the formation of NaZn13 phase.
► Cu substitution in La0.7Pr0.3Fe11.4−xCuxSi1.6 leads to a reduction in hysteresis loss.
► Replacement Fe by Cu leads to increase in the Curie temperature (TC).
► Increasing Cu composition indicated to decreases the magnetic entropy.
► Highest Cu concentration with x = 0.34 effected to structural stability of NaZn13.