Magnetic properties and magnetocaloric effect in the RCu2Si2 and RCu2Ge2 (R = Ho, Er) compounds

Abstract

The magnetic properties and magnetocaloric effect (MCE) in RCu2Si2 and RCu2Ge2 (R = Ho, Er) compounds have been investigated. All these compounds possess an antiferromagnetic (AFM)-paramagnetic (PM) transition around their respective Neel temperatures. The RCu2Si2 compounds undergo spin-glassy behavior above Neel temperature. Furthermore, a field-induced metamagnetic transition from AFM to ferromagnetic (FM) states is observed in these compounds. The calculated magnetic entropy changes show that all RCu2Si2 and RCu2Ge2 (R = Ho, Er) compounds, especially, ErCu2Si2 exhibits large MCEs with no thermal hysteresis and magnetic hysteresis loss. The value of −ΔSMmax reaches 22.8 J/Kg K for magnetic field changes from 0 to 5 T. In particular, for field changes of 1 and 2 T, the giant reversible magnetic entropy changes −ΔSMmax are 8.3 and 15.8 J/kg K at 2.5 K, which is lower than the boiling point of helium. The low-field giant magnetic entropy change, together with ignorable thermal hysteresis and field hysteresis loss of ErCu2Si2 compound is expected to have effective applications in low temperature magnetic refrigeration.

Development of magnetic refrigeration materials andtechnology

“…三元低温磁制冷材料按结构分主要有ZrNiAl型 [50][51][52][53][54][55][56][57][58] 、 MgZn 2 型 [59] 、CeFeSi型 [60] 、ThCr 2 Si 2 型 [61] 、AlB 2 型 [62,63] 等.…”

“…Ho, Er, Tm)稀土金属间化合物的相变温度从Gd的50 K 降低到Tm的2 K [59][60][61][62][63][64] . GdCuAl和TbCuAl属于反铁磁材 料 [52,53] , 而R=Dy, Ho, Er, Tm属于铁磁性材料 [54][55][56] .…”

“…图 11 (网络版彩图) ErCu 2 Si 2 在不同磁场下的磁熵变化曲 线 [61] Figure 11 (Color online) The magnetic entropy change curve of ErCu 2 Si 2 in different magnetic fields [61].…”

Effect of Cu doping on the magnetic and magnetocaloric properties in the HoNiAl intermetallic compound

“…Except for these materials, numberous materials such as PrGa [6], R 2 CuSi 3 [7], Eu 4 PdMg [8], GdCoAl [9], Ho(Co 1Àx Al x ) 2 [10], La 0.5 Ca 0. 4 Li 0.1 MnO 3 [11], RCu 2 Si 2 and RCu 2 Ge 2 (R = Ho, Er) [12], R 15 Si 9 C [13] as well as amorphous alloys [14] have been reported in mainstream magazines in the last few months. On the other hand, RNiAl (R = rare-earth metal) and RCuAl have been extensively studied for their interesting magnetic properties and their capability serving as potential magnetic refrigerants used in cryogenic temperature region and suitable for special applications in space science and so on [15][16][17][18][19][20].…”

Structural, Thermoelectric, Electronic, and Magnetic Properties of Pristine Intermetallic Rare-Earth-Based XMn2Si2 (X=Dy, Er) Compounds

“…Investigations into the RT 2 X 2 family for magnetocaloric effect (MCE) have recently been carried out in various works. As a result, various compounds, including TbMn 2 Si 2 22 and ErT 2 Si 2 (T=Mn, Cu and Cr), 23 have been found to have enormous MCE.…”