| Summary: | In this experiment, a series of MnCoGe<sub>1−x</sub>La<sub>x</sub> (x = 0, 0.01, 0.03) alloy samples were prepared using a vacuum arc melting method. The crystal structure and magnetic properties of alloys were investigated using X-ray diffraction (XRD), Rietveld method, physical property measurement system (PPMS), and vibrating sample magnetometer (VSM) analyses. The results show that all samples were of high-temperature Ni<sub>2</sub>In-type phases, belonging to space group P6<sub>3</sub>/mmc (194) after 1373 K annealing. The results of Rietveld refinement revealed that the lattice constant and the volume of MnCoGe<sub>1−x</sub>La<sub>x</sub> increased along with the values of La constants. The magnetic measurement results show that the Curie temperatures (T<sub>C</sub>) of the MnCoGe<sub>1−x</sub>La<sub>x</sub> series alloys were 294, 281, and 278 K, respectively. The maximum magnetic entropy changes at 1.5T were 1.64, 1.53, and 1.56 J·kg<sup>−1</sup>·K<sup>−1</sup>, respectively. The respective refrigeration capacities (RC) were 60.68, 59.28, and 57.72J·kg<sup>−1</sup>, with a slight decrease along the series. The experimental results show that the doping of La results in decreased T<sub>C</sub>, basically unchanged magnetic entropy, and slightly decreased RC.
|
|---|