Anisotropy-enhanced giant reversible rotating magnetocaloric effect in HoMn2O5 single crystals

Abstract

Magnetic and magnetocaloric properties of HoMn2O5 single crystals were investigated. HoMn2O5 undergoes a large conventional magnetocaloric effect around 10 K. The magnetocaloric effect was found to present a giant anisotropy. Consequently, a large magnetocaloric effect (−ΔSR,max= 12.43 J/kg K for 7 T) can be obtained simply by rotating the single crystal HoMn2O5 within the cb plane in constant magnetic field instead of moving it in and out of the magnetic field zone. This can open the way for the implementation of compact, simplified, and efficient rotary magnetic refrigerators.

Analysis of the Anisotropic Magnetocaloric Effect in RMn2O5 Single Crystals

“…In this context, the RMn 2 O 5 (R = magnetic rare-earth element) multiferroics seem to be alternative candidates for magnetocaloric tasks around 10 K [15,16,[25][26][27][28][29]. These compounds unveil complex crystalline and magnetic structures which results in a wide range of fascinating electrical and magnetic…”

“…However, the search for materials with excellent magnetocaloric properties in the temperature range from about 2 to 30 K is of great interest from fundamental, practical, and economical points of view, due to their potential use as refrigerants in several low temperature applications such as the space industry, scientific instruments, and gas liquefaction [14][15][16][17][18][19][20][21][22][23][24][25]. On the other hand, the development of new designs that can render magnetic cooling more competitive is also a key parameter for the commercialization of this emergent technology.…”

Effect of Gd polarization on the large magnetocaloric effect ofGdCrO4in a broad temperature range

“…In oxides, similar examples are abundant, especially for rare-earth transition metal oxides. Gd 3 Ga 5 O 12 (GGG) [6], RMnO 3 [7], RMn 2 O 5 [8], and EuR 2 O 4 [9], where R = rare earth, present high thermal and chemical stabilities and display large MCEs in the low-temperature region. New families without rare earths in their compositions have also been investigated as materials for refrigeration purposes close to room temperature [10].…”

Large rotating magnetocaloric effect in ErAlO3 single crystal

“…A gradual increase in -∆S R (θ) can be seen as the magnetic field is rotated from the b to c axis and reaches a maximum value. In a field of 5 T, the maximum value of -∆S R (θ) is 9.7 J/kg K, which is comparable with or even large than those reported in some single crystals such as TbMnO 3 (9.2 J/kg K), 11 TmMnO 3 (5 J/kg K), 12 (10 J/kg K), 14 TmFeO 3 (9.0 J/kg K), 19 in similar temperature range. Magnetocrystalline anisotropy and thermal fluctuation are reported to contribute to the large rotating field entropy change.…”

“…Magnetocrystalline anisotropy and thermal fluctuation are reported to contribute to the large rotating field entropy change. 12,14 Following the coherent rotation (CR) model described in Ref. 11,12, we begin to discuss the origination of large rotating field entropy change in ErAlO 3 single crystal here.…”