The influence of partial substitution of La by Dy on structure and thermomagnetic properties of the LaFe_(11.0)Co_(0.7)Si_(1.3) alloy

摘要

The aim of the following paper was to study the structure and magnetocaloric effect of the La1−xDyxFe11.0Co0.7Si1.3alloys (where x = 0, 0.1, 0.2). The X-ray diffraction showed a coexistence of two phases: the dominant La(Fe,Si)13and minor α-Fe. The Rietveld analysis revealed a gradual decrease in the lattice constant of the La(Fe,Si)13structure with increase in Dy addition. Moreover, the Curie temperature reached 267, 265.5 and 269 K for x = 0, 0.1 and 0.2, respectively. The values of magnetic entropy change equaled 14.6, 11.2 and 9.2 J(kg K)−1for the LaFe11.0Co0.7Si1.3, La0.9Dy0.1Fe11.0Co0.7Si1.3and La0.8Dy0.2Fe11.0Co0.7Si1.3alloys, respectively. The values of exponent n (according to ΔSM = C·(BMAX)n) calculated at the Curie temperature were 0.67 for base sample and 0.70 for specimens modified by Dy. The determined values correspond well with theoretical predictions.