The magnetic properties and magnetocaloric effects in binary R-T (R = Pr, Gd, Tb, Dy, Ho, Er, Tm; T = Ga, Ni, Co, Cu) intermetallic compounds

In this paper, we review the magnetic properties and magnetocaloric effects (MCE) of binary R-T (R = Pr, Gd, Tb, Dy, Ho, Er, Tm; T = Ga, Ni, Co, Cu) intermetallic compounds (including RGa series, RNi series, R12Co7 series, R3Co series and RCu2 series), which have been investigated in detail in the past several years. The R-T compounds are studied by means of magnetic measurements, heat capacity measurements, magnetoresistance measurements and neutron powder diffraction measurements. The R-T compounds show complex magnetic transitions and interesting magnetic properties. The types of magnetic transitions are investigated and confirmed in detail by multiple approaches. Especially, most of the R-T compounds undergo more than one magnetic transition, which has significant impact on the magnetocaloric effect of R-T compounds. The MCE of R-T compounds are calculated by different ways and the special shapes of MCE peaks for different compounds are investigated and discussed in detail. To improve the MCE performance of R-T compounds, atoms with large spin (S) and atoms with large total angular momentum (J) are introduced to substitute the related rare earth atoms. With the atom substitution, the maximum of magnetic entropy change (Delta S-M), refrigerant temperature width (T-width) or refrigerant capacity (RC) is enlarged for some R-T compounds. In the low temperature range, binary R-T (R = Pr, Gd, Tb, Dy, Ho, Er, Tm; T = Ga, Ni, Co, Cu) intermetallic compounds (including RGa series, RNi series, R12Co7 series, R3Co series and RCu2 series) show excellent performance of MCE, indicating the potential application for gas liquefaction in the future.