Spin-Glass-like State and Reversible Room-Temperature Magnetocaloric Effect in Double Distorted Perovskites Nd(Cu_3–xMn_x)Mn₄O₁₂

Abstract

The preparation, complex magnetic properties and room-temperature magnetocaloric effect in Nd(Cu 3−x Mn x )-Mn 4 O 12 with cation distribution (Nd 3+ ) A (Cu 3−x 2+x Mn x 3+ ) A′ (Mn 1+x 3+ Mn 3−x 4+ ) B O 12 2− (x = 1 and 1.5) have been reported. Both compounds show a sharp paramagnetic-ferromagnetic (FM) transition at T C of 300 and 280 K, respectively. The substitution of Cu by Mn at the A′ site induces the emergence of a spin glass state below ≈63 K for x = 1 and ≈72 K for x = 1.5 compound. Another antiferromagnetic-like magnetic transition is also observed in both compounds at 23 and 28 K, respectively, which is discussed as the antiferromagnetic coupling between Nd 3+ at the A′ site and (Mn 3+ /Mn 4+ ) at the B site. These two compounds exhibit roomtemperature magnetocaloric effect. For a small field of 2 T, the maximum magnetic entropy changes −ΔS M are 1.5 J/kg K at 300 K and 1.4 J/kg K at 280 K, respectively. Moreover, the −ΔS M (T) curves show an asymmetric distribution, resulting in high refrigerant capacity values for both compounds. We further demonstrate the distinct roles of the A′-and B-site spins on the magnetic properties and the origin of the spin-glass-like state in double distorted perovskites Ln(Cu 3−x Mn x )Mn 4 O 12 family of compounds.

First principles calculation to investigate the effect of Mn substitution on Cu site in CeCu3−xMnxV4O12 (x = 0, 1, 2 and 3) system

“…30 ) and from ferromagnetic to anti-ferromagnetic in RCu 3 Mn 4 O 12 (R = Nd and Pr) 31 and recently spin glass state is reported in NdCu 3 Mn 4 O 12 by Mn substitutions at Cu site. 32 Keeping in view the effect of substitution at Cu site, the present study is performed to investigate the electronic structure in addition to elastic, thermoelectric and magnetic properties. The exchange correlation GGA, GGA with Hubbard U and HF are used within the WEIN2K package following the density functional theory (DFT) techniques for cutting-edge magnetic memory devises and spintronic technology.…”