Structural, magnetic and magnetocaloric properties in distorted RE ₂NiTiO₆ double perovskite compounds

Abstract

The magnetocaloric effect (MCE) based Magnetic refrigeration (MR) was considered a novel energy-efficient and environmentally benign cooling method. However, the lack of suitable magnetic solids has slowed the development of its practical applications. We herein fabricated the RE2NiTiO6 (RE = Gd, Tb and Ho) double perovskite (DP) compounds and systematically determined their structural, magnetic and magnetocaloric properties by experimental determination and density functional theory (DFT) calculations, in which the Gd2NiTiO6 was realized to exhibit promising cryogenic magnetocaloric performances. The results indicated that all the RE2NiTiO6 DP compounds crystallized in a distorted monoclinic structure with P21/n space group and underwent a second order type magnetic phase transition around 4.3, 4.5 and 3.9 K, for Gd2NiTiO6, Tb2NiTiO6 and Ho2NiTiO6, respectively. The magnetocaloric performances were checked by the parameters of maximum magnetic entropy change and relative cooling power, which are 31.28 J/kg∙K and 242.11 J/kg for Gd2NiTiO6, 13.08 J/kg∙K and 213.41 J/kg for Tb2NiTiO6, 11.98 J/kg∙K and 221.73 J/kg for Ho2NiTiO6 under the magnetic field change of 0-50 kOe, respectively. Evidently, the Gd2NiTiO6 compound exhibit promising magnetocaloric performances and therefore is of potential for practical cryogenic MR applications.

B-site disorder driven Griffiths-like phase and electrochemical behavior in Y2NiCrO6 double perovskite

“…Wyc. positions, bond lengths, and bond angles which are in good agreement with the reported values in the octahedral oxygen environment of related double perovskites [57,58]. The absorption peaks at 439 cm −1 , 504 cm −1 , and 584 cm −1 with the prominent peak at 706 cm −1 can be ascribed to the stretching and bending vibrations of the metal-oxygen (Ni/Cr-O) bonds within the NiO 6 /CrO 6 octahedra of the YNCO compound [13,59,60].…”

Magnetocaloric effect and Griffiths phase analysis in a nanocrystalline Ho2NiMnO6 and Ho2CoMnO6 double perovskite

“…It was found that in case of Gd 2 NiTiO 6 compound MCE properties are better than other two compounds. 35 The transition temperature and magnetocaloric effect can be enhanced by substituting non-magnetic Ti 3+ ion in Gd 2 CoMnTiO 6 compound by Zheng et al 36 It was found that MCE enhanced from 16.64 J kg −1 K −1 to 27.16 J kg −1 K −1 under Δ H = 6 T at cryogenic temperature. Patra et al 37 reported the synthesis of Ho 2 CoMnO 6 nanorod by using hydrothermal route and magnetocaloric effect gives a change in entropy value of 12.4 J kg −1 K −1 at low temperature for 7 T.…”

“…25 Among the double perovskite families, R 2 MMnO 6 (R = rare earth element, M = Ni, Co) has recently attracted substantial interest due to its controllability of magnetic and electronic properties. 26,27 These DP compounds contain Co 2+ ions with electronic conguration d 7 tse 2 g and Mn 4+ with electronic conguration d 3 t 2 g 3 e 0 g , which exhibit ferromagnetic ordering due to Co 2+ and Mn 4+ superexchange interactions. 28,29 These types of DP compounds are mostly ferromagnetic and insulating, with the formation of ferromagnetic cluster.…”

Designing magnetocaloric materials for hydrogen liquefaction with light rare-earth Laves phases

“…other industrial gases [13][14][15][16][17][18][19][20][21][22][23][24][25]. The emerging magnetocaloric liquefaction technology is in principle more efficient [5,[26][27][28][29][30][31][32], making the promise of hydrogen fuel being affordable for the society to reach climate-neutrality.…”