Giant magnetocaloric effect in Ho12Co7 compound

Abstract

Magnetic properties and magnetocaloric effects of Ho12Co7 compound are investigated by magnetization and heat capacity measurement. The Ho12Co7 compound undergoes antiferromagnetic (AFM)-AFM transition at T1 = 9 K, AFM-ferromagnetic (FM) transition at T2 = 17 K, and FM-paramagnetic transition at TC = 30 K, with temperature increasing. There are two peaks on the magnetic entropy change (ΔSM) versus temperature curves and the maximal value of –ΔSM is found to be 19.2 J/kg K with the refrigerant capacity value of 554.4 J/kg under a field change from 0 to 5 T. The shape of the ΔSM-T curves obtained from heat capacity measurement is in accordance with that from magnetization measurement. The excellent magnetocaloric performance indicates the applicability of Ho12Co7 as an appropriate candidate for magnetic refrigerant in low temperature ranges.

Nearly constant magnetic entropy change and adiabatic temperature change in PrGa compound

“…[1][2][3] Magnetic refrigeration is based on magnetocaloric effect (MCE), and the materials used for magnetic refrigeration are mainly evaluated by two important parameters: isothermal magnetic entropy change (DS M ) and adiabatic temperature change (DT). 4 Lots of materials with large DS M near room temperature have been found such as Gd 5 Si 2 Ge 2 , MnFeP 1Àx As x , MnAs 1Àx Sb x , La(Fe, M) 13 (M ¼ Si, Al), and NiMnGa. [5][6][7][8][9][10] And many materials showing large DS M in low temperature range have also been studied, as they can be used for gas liquefaction.…”

“…[5][6][7][8][9][10] And many materials showing large DS M in low temperature range have also been studied, as they can be used for gas liquefaction. [11][12][13][14] In most cases, the curves of DS M or DT are peak like distribution and platforms can be observed only for certain materials near room temperature region such as LaFe 11.8 Si 1.2 and LaFe 11.44 Al 1.56 . 15,16 The feature of nearly constant DS M or DT in a wide temperature range is very important for practical applications of materials.…”

Large magnetocaloric effect of NdGa compound due to successive magnetic transitions

“…Lots of MCE materials with large value of ∆S M have been obtained and studied in room temperature range. [6][7][8][9][10][11][12][13] In recent years, lots of attention have also been paid on the magnetic materials with low transition temperatures, for this kind of MCE materials can be used for liquefaction, 14,15 such as TmZn, 16 RNi (R=Ho, Er), 17,18 R 12 Co 7 (R=Ho, Er) [19][20][21][22][23] and HoCoSi. 24 Especially the magnetic compounds with successive transitions show advantage on δT FWHM and RC and thus researchers are inclined to explore MCE materials in those with several magnetic transitions.…”

Complex magnetic properties and large magnetocaloric effects in RCoGe (R=Tb, Dy) compounds

“…3,4 Recently, it has been anticipated to be widely used in room temperature in the near future. 5 Many excellent magnetocaloric materials have been reported in detailed, such as Gd 5 Si 2 Ge 2 , MnFeP 1-x As x , MnAs 1-x Sb x , La(Fe, M) 13 (M=Si, Al), and NiMnGa. [6][7][8][9][10][11] In addition to common applications such as domestic refrigerators, many materials showing large ∆S M in low temperature range have also been studied, as they are important for basic research as well as special technological applications.…”

“…[6][7][8][9][10][11] In addition to common applications such as domestic refrigerators, many materials showing large ∆S M in low temperature range have also been studied, as they are important for basic research as well as special technological applications. [12][13][14][15][16] The RTX (R = rare earth, T = transition metal, and X = p-block metal) family compounds with various crystalline structures have been explored extensively because of their rich magnetic and electrical transport properties. [17][18][19] Recently, lots of attentions have been paid to…”