Effect of M/NM ratios on structural and magnetic properties of (Mn,Fe)2(P, Si) compounds

作者：Li, C. F.; Zheng, Z. G.^*; Wang, W. H.; Liu, J. Y.; Lei, L.; Zeng, D. C.^*

来源：Physica B: Condensed Matter , 2020, 594: 412309.

DOI：10.1016/j.physb.2020.412309

• Magnetocaloric effects
• (Mn,Fe)(2)(P,Si) compounds
• Phase transition
• Magnetic properties

The (Mn,Fe)(2)(P,Si) compounds with large magnetocaloric effect are sensitive to the contents of impurity phase. In order to decrease its contents, the (MnFe)(delta)(P0.5Si0.5) (delta = 1.90, 1.95, 2.00, 2.05) compounds were designed and prepared by arc-melting method. The structure and magnetic properties were characterized by XRD, SEM, DSC and VSM, respectively. The diffraction analysis reveals that all samples are hexagonal Fe2P-type crystals with some impurity phase. The structure of impurity phase would change from cubic (Mn,Fe)(3)Si to hexagonal (Mn,Fe)(5)Si-3 with decreasing delta from 2.05 to 1.90. And the Curie temperature of (MnFe)(delta)(P0.5Si0.5) compounds increased from 234 K for delta = 2.05 to 371 K for delta = 1.90. Meanwhile, the thermal hysteresis decreased by 58%. Under the field change of 5 T, the peak values of isothermal entropy change reaches 19.6 J.kg(-1).K-1 for delta = 1.95. While, the maximal adiabatic temperature change increased by 47% as delta decreasing from 2.05 to 1.90. All results show that the impurity phase and magnetic properties of the (Mn,Fe)(2)(P,Si) compounds can be effectively tuned by adjusting M/NM ratios.