In this experiment, a series of MnCoGe1−xLax (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 Ni2In-type phases, belonging to space group P63/mmc (194) after 1373 K annealing. The results of Rietveld refinement revealed that the lattice constant and the volume of MnCoGe1−xLax increased along with the values of La constants. The magnetic measurement results show that the Curie temperatures (TC) of the MnCoGe1−xLax 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−1·K−1, respectively. The respective refrigeration capacities (RC) were 60.68, 59.28, and 57.72J·kg−1, with a slight decrease along the series. The experimental results show that the doping of La results in decreased TC, basically unchanged magnetic entropy, and slightly decreased RC.

No abstract

Rare earth noble metals compounds have a variety of physical properties, such as heavy fermions, topological, superconductivity, and so on. In this paper, the cohesive energy, mechanical, electrical, and magnetic properties of REAuBi2 (RE=La-Pr, Sm) and the mechanical properties of REAu (RE=La-Pr, Sm) were studied by first-principles calculations. The calculated cohesive energies of REAuBi2 are negative, indicating the stable structures of REAuBi2. The comparison between the mechanical properties of REAuBi2 and REAu, including the bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio, under ideal conditions is carried out. Electronic density of states, band structure, and phonon spectrum of REAuBi2 are also studied and discussed. LaAuBi2 alloy is in the paramagnetic state, while PrAuBi2 and SmAuBi2 alloys are in antiferromagnetic order obtained by the results of Birch–Murnagha equation fitting of cell volume and energy.

No abstract

No abstract