In this paper, we report the structural, magnetic and magnetocaloric properties of Ni-doped La0.67Ba0.33Mn1−xNixO3 (x = 0, 0.025 and 0.075) manganites. Our compounds were synthesized using the sol–gel method. The structural analysis… Click to show full abstract
In this paper, we report the structural, magnetic and magnetocaloric properties of Ni-doped La0.67Ba0.33Mn1−xNixO3 (x = 0, 0.025 and 0.075) manganites. Our compounds were synthesized using the sol–gel method. The structural analysis using Rietveld refinement shows that Ni-doped LaBaMnO3 system crystallizes in the rhombohedral symmetry with $${\text{R}}\bar {3}{\text{c}}$$R3¯c space group. Magnetization measurements versus temperature in a magnetic applied field of 0.05 T reveal that all the compositions exhibit a transition from a ferromagnetic to paramagnetic phase with increasing temperature. A systematic decrease in the transition temperature is clearly observed upon Ni doping and a near room temperature TC (302 K) is achieved with x = 0.075 composition. The maximum magnetic entropy change $$\left( { - ~\Delta {\text{S}}_{{\text{M}}}^{{\hbox{max} }}} \right)$$-ΔSMmax in a magnetic field change of 5 T is found to be 2.12, 2.78 and 1.78 J/kg K for x = 0, 0.025 and 0.075, respectively. At this value of magnetic field, large relative cooling power values are obtained in our samples, especially for x = 0.075 (271 J/kg) making it a promising candidate for magnetic refrigeration near room temperature.
               
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