Structural and magnetic properties, magnetocaloric effect in (La 0.7 Pr 0.3 ) 0.8 Sr 0.2 Mn 0.9 Ti 0.1 O 3±δ (δ = 0.03, 0.02, −0.03)

Abstract Structural and magnetic properties of the compositions (La 0.7 Pr 0.3 ) 0.8 Sr 0.2 Mn 0.9 Ti 0.1 O 3±δ prepared at different oxygen partial pressures were investigated over a wide temperature range. The temperatures of phase structural transitions were found; their values varied significantly depending on the oxygen index δ. The first structural transition was due to the cooperative Jahn-Teller effect occurred within the orthorhombic system. The second transition occurs at a higher temperature at which the orthorhombic phase transformed into a rhombohedral phase. The temperature of this transition increased with increasingδ and was equal to ∼323 K (δ = +0.03), 353 K (δ = +0.02)and 623 K (δ = −0.03). The temperature dependence of the magnetization evidenced that all compositions exhibited a ferromagnetic to paramagnetic transition at T C  = 132–149 K. The transition temperature was found to increase with increasing oxygen content. It was shown that the phase transition from ferromagnetic to paramagnetic state was of the second order. The magnetic entropy change was calculated from the isothermal magnetization curves obtained at different temperatures. A magnetocaloric effect over a wide temperature range in the vicinity of T C with a maximum magnetic entropy change of ∼1 J/kg K and the relative cooling power of 120 J/kg under the applied field of 2 T was found. The relatively large value and broad temperature interval of the magnetocaloric effect make (La 0.7 Pr 0.3 ) 0.8 Sr 0.2 Mn 0.9 Ti 0.1 O 3 compound a promising candidate for magnetic refrigerant.