Anisotropic magnetic entropy change in RFeO3 single crystals(R = Tb, Tm, or Y)

Abstract

Compared with traditional gas-compression/expansion refrigeration, magnetic refrigeration based on magnetocaloric effect (MCE) exhibits the advantages of high energy efficiency and environment friendliness. Here, we created large MCE in RFeO3 (R = Tb or Tm) single crystals by the magnetization vector rotation of single crystal with strong magnetocrystalline anisotropy (MCA), rather than merely via the order-disorder magnetic phase transition or magnetic structural transition. Owing to the difference in charge distribution of 4f-electrons between Tb3+ and Tm3+ ions, the rotating field entropy with different signs, −ΔSMR = 17.42 J/kg K, and –ΔSMR = −9.01 J/kg K are achieved at 9 K and 17 K for TbFeO3 and TmFeO3 single crystals from b axis to c axis, at 50 kOe, respectively. The finding of the large anisotropic MCE not only advances our understanding of the anisotropy of MCE, but also extends the application for single crystals to magnetic refrigeration.

Review of the Magnetocaloric Effect in RMnO3 and RMn2O5 Multiferroic Crystals

“…However, its refrigerant capacity remains comparable with that presented by the orthorhombic DyMnO3 (Figure 11) but lower if compared with the HoVO3 vanadate [28]. On the other hand a large rotating entropy change that is comparable with that exhibited by oDyMnO3 crystals [24] was more recently reported in TbFeO3 (-ΔSR = 17.42 J/kg K at 5 T) around 9 K [96]. These data underline the high potential of R(Ti, Fe)O3-based compounds in cryomagnetocaloric applications.…”

“…These data underline the high potential of R(Ti, Fe)O 3 -based compounds in cryomagnetocaloric applications. In addition to RMnO3 manganites, the RTiO3 (titanates) [93][94][95] and RFeO3 [96] compounds emerge also as promising magnetocaloric materials for cryogenic applications. Particularly, a giant magnetocaloric effect was pointed out in EuTiO3 single crystals [93].…”

Giant magnetocaloric effect in an exchange-frustrated GdCrTiO5 antiferromagnet

“…Several rare-earth element based transition metal oxides and intermetallic compounds carrying high magnetic moments have become attractive candidates for the low-temperature magnetic refrigeration. [21][22][23][24][25][26][27][28][29][30] In these materials, the rare-earth magnetic moments order at low temperature and a strong suppression of the magnetic entropy takes place in the vicinity of the order-disorder phase transition with the application of magnetic field. However, the value of the magnetic entropy, ∆S m , decreases rapidly and becomes very small just few Kelvin below the transition temperature and thereby limits the lowest temperature achievable by the magnetic refrigeration technique.…”

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.…”