Magnetic properties and magnetocaloric effects of RNiSi2 (R= Gd, Dy, Ho, Er, Tm) compounds

摘要

Orthorhombic CeNiSisub2/sub-type polycrystalline RNiSisub2/sub (R=Gd, Dy, Ho, Er, Tm) compounds were synthesized and the magnetic and magnetocaloric properties were investigated in detail. The transition temperatures of RNiSisub2/sub compounds are all in a very low temperature range (30 K). As temperature increases, all of the compounds undergo an AFM to PM transition (GdNiSisub2/sub at 18 K, DyNiSisub2/sub at 25 K, HoNiSisub2/sub at 10.5 K, ErNiSisub2/sub at 3 K and TmNiSisub2/sub at 3.5 K, respectively). ErNiSisub2/sub compound shows the largest ( Δ S M ) m a x (maximal magnetic entropy change) among these compounds. The value of ( Δ S M ) m a x is 27.9 J/kgK under a field change of 0-5 T, which indicates that ErNiSisub2/sub compound is very competitive for practical applications in low-temperature magnetic refrigeration in the future. DyNiSisub2/sub compound shows large inverse MCE (almost equals to the normal MCE) below the TsubN/sub which results from metamagenitic transition under magnetic field. Considering of the normal and inverse MCE, DyNiSisub2/sub compound also has potential applications in low-temperature multistage refrigeration.