Magnetocaloric properties of the hexagonal HoMnO3 single crystal revisited

Review of the Magnetocaloric Effect in RMnO3 and RMn2O5 Multiferroic Crystals

“…This includes compounds such as TbMnO3 and GdMnO3 for example. When the ionic radius of R is smaller than that of Dy as in HoMnO3 and ErMnO3, the RMnO3 compounds form in a hexagonal structure with space group P63cm [27,[65][66][67][68]. It is worth noting that the DyMnO3 compound is usually more stable in the orthorhombic structure at room temperature.…”

“…The RMnO3 (R = rare earth) manganites have generated worldwide interest due to their rich physical properties and potential implementation in a wide range of applications going from spintronics such as four state memory systems [37] to magnetocaloric refrigeration [20][21][22][23][24]26,27]. In these highly frustrated multiferroics, the magnetic, electric and crystallographic structures are markedly coupled and strongly depend on the rare earth element size (rR) [22,27,[65][66][67][68].…”

“…In addition, as claimed by Barclay et al [18], a large scale utilization of hydrogen as a source of energy will result in better energy security with major environmental, economic, and social benefits. In this context, several cryomagnetocaloric materials have been proposed [19][20][21][22][23][24][25][26][27][28]. Following this, Matsumoto et al [29,30] unveiled a reciprocating magnetic refrigerator dedicated to hydrogen liquefaction that uses the Dy 2.4 Gd 0.6 Al 5 O 12 garnet as refrigerant.…”

“…Especially, some of these systems show a strong coupling between magnetism and ferroelectricity which provides an additional degree of freedom regarding the design of magnetoelectric effect-based machines [30][31][32][33][34][35][36][37][38][39][40]. On the other hand, the investigation of their magnetocaloric properties has unveiled a great potential for application in magnetic refrigeration at low temperature regime [19][20][21][22][23][24][25][26][27][28]. This means that more than one task can be achieved by only using a single RMn 2 O 5 or RMnO 3 material which is of great interest from an economical point of view.…”

Analysis of the Anisotropic Magnetocaloric Effect in RMn2O5 Single Crystals

“…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.…”