Influence of High-Pressure Nitrogenation on the Structural, Magnetic and Magnetocaloric Properties of La0.5Pr0.5Fe11.4Si1.6

Autor: Ping-Zhan Si, Sheng-Jie Du, Zengxin Ren, Jie Guo, Naikun Sun
Rok vydání: 2015
Předmět:
Zdroj: Acta Metallurgica Sinica (English Letters). 28:1382-1386
ISSN: 2194-1289
1006-7191
DOI: 10.1007/s40195-015-0336-3
Popis: Nitrogenation of La0.5Pr0.5Fe11.4Si1.6 with a particle size of 100–150 μm was performed in a high-purity N2 atmosphere of 40 MPa. La0.5Pr0.5Fe11.4Si1.6N0.3 nitrogenated at 480 °C exhibits an increase in the Curie temperature T C from 187 to 195 K. Moreover, for a field change from 0 to 1.5 T, the maximum hysteresis loss at T C is remarkably reduced from 53 to 3 J kg−1 and a large magnetic-entropy change ΔS m of over 10 J kg−1 K−1 is maintained. For a La0.5Pr0.5Fe11.4Si1.6N1.2 sample, nitrogenated at 550 °C, the XRD pattern clearly exhibits two 1:13 phases and, accordingly, the thermal magnetic curves exhibit two transitions, at 210 and at 295 K. The two transitions lead, for a field change of 5 T, to a ΔS m larger than 2 J kg−1 K−1 over a large temperature range from 200 to 310 K with a maximum value of 5.3 J kg−1 K−1 at 225 K. Upon further increase in the nitrogenation temperature to 650 °C, the amount of the nitrogen-poor phase strongly decreases and a large amount of α–Fe precipitates, resulting in a large reduction in the MCE.
Databáze: OpenAIRE
Externí odkaz: