Magnetism and magnetocaloric effect in nanocrystalline La_0.67Ca_0.33Mn_0.9V_0.1O₃synthesized by nebulized spray pyrolysis

Abstract

Vanadium (V) substituted La0.67Ca0.33MnO3 was synthesized in the nanocrystalline form using nebulized spray pyrolysis. Highly uniform nanoparticles of average size in the range 30–40 nm as revealed by transmission electron microscopic studies were prepared. Rietveld refinement of XRD patterns shows that the sample adopts an orthorhombic structure with the Pnma space group. The systematic change in lattice parameters and magnetic phase transition (TC = 252 K) as compared with those of nanocrystalline La0.67Ca0.33MnO3 (TC = 260 K) indicate the substitutional effect of V. M–H curves in a certain temperature range reflect the superparamagnetic nature of the sample. The average particle size (∼28 nm) of the superparamagnetic clusters obtained from the Langevin fit is coincident with that of the nanocrystalline clusters revealed by the high-resolution transmission electron microscopy images. The Arrott plots reveal the first order character of magnetic phase transition of the sample. The peak magnetic entropy change (ΔSmax) of these nanopowders is estimated to be about 4.5 J kg−1 K−1 for a magnetic field of 5 T at 252 K. Compared with the bulk La0.67Ca0.33Mn0.9V0.1O3, the entropy change of the nanoparticles is found to be smaller, but the entropy change occurs over a broad temperature range, giving rise to a large relative cooling power.

Critical behaviour and magnetocaloric effect of nano crystalline La0.67Ca0.33Mn1−xFexO3 (x = 0.05, 0.2) synthesized by nebulized spray pyrolysis

“…Very little attention has been paid on the effect of particle size on the magnetocaloric effect. Nano materials are good candidates for low cost magnetic refrigerants because they can offer much better to the desired entropy change and the temperature change than that of their bulk counterparts [19]. A number of synthesis techniques like solid state synthesis, sol gel, polymer precursor, citrate gel, coprecipitation [20e24] have been reported in the literature for the preparation of bulk/nano alkaline earth substituted lanthanum manganite like La 0.67 Ca 0.33 MnO 3 .…”

Effect of Fe-doping on Magnetocaloric Properties of AMn1−x Fe x O3 Compounds (0≤x≤0.2)

“…Below T C , M(T , μ 0 H ) curves increase sharply with applied magnetic field for 0.5 T and then saturate above 1 T. Theses curves reveal a strong variation of magnetization around the Curie temperature. The magnetic entropy is related to the magnetization M, magnetic field strength μ 0 H , and absolute temperature T through the Maxwell relation [13,14]:…”

Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites

“…. ), have roused plenty of research thanks to their important electrical and magnetic properties, such as the colossal magnetoresistance (CMR) [2][3][4][5][6][7][8] and the magnetocaloric effect (MCE) [9][10][11][12][13][14]. That is why the parameter necessary for selecting magnetic refrigerants is based on the cooling power per unit volume and the relative cooling power (RCP).…”