Magnetocaloric Effects of La_0.8R_0.2(Fe_0.88Si_0.12)₁₃ (R = Y, Ho and Yb) Compounds in Low Applied Magnetic Field

抄録

Low field magneto-caloric response is important for application. We present here the results of a study on crystal structure and magnetic properties of rare-earth doped compounds La_0.8R_0.2(Fe_0.88Si_0.12)₁₃ (R = Y, Ho and Yb). All samples were prepared by using arc-melting method in argon atmosphere. The lattices revealed by X-ray diffraction method show a well-defined NaZn₁₃-type structure with small amounts of α-Fe phase. The dependence of magnetization on temperature M(T) and on field M(H) curves were recorded. The magnetic entropy change −ΔS_m and cooling powers (RCP) of compounds were estimated. The results show considerable better magneto-caloric responses of doped compounds in comparison with that of the undoped compound.

Fig. 1 X-ray diffraction patterns of La_0.8R_0.2(Fe_0.88Si_0.12)₁₃ compounds. The diffractograms of Sm and Tb doped compounds are taken from Ref. 13) for comparision. The inset shows the increase of lattice constants upon the increase of ionic radius of substituted element.