X-ray diffraction pattern of Sm0.7−xLaxSr0.3MnO3 (x = 0–0.7) compounds.
Phase diagram for Sm0.7−xLaxSr0.3MnO3 (x = 0–0.7) as a function of tolerance factor t and composition x. Tc and T* correspond to ferromagnetic Curie temperature of the Mn-sublattice and occurrence of a cusp in the field-cooled magnetization measured at μ0 H = 1 kOe, respectively.
(a) Temperature dependence of the resistivity ρ(T) of x = 0–0.6 in zero magnetic field. The inset shows the activation energy for polaron hopping with varying x. (b) ln(ρ/T) versus 1/T plots with linear fit at high temperatures for x = 0 and 0.1.
(a) Field-cooled magnetization M(T) for x = 0–0.7 under H = 1 kOe. (b) M(H) at 10 K for x = 0, 0.1, 0.4, and 0.6. The inset (i) shows dependence of magnetization value at 5 T at 10 K on composition. The inset (ii) shows Tc and T* as a function of composition x.
M(H) plots at selected temperatures for x = (a) 0, (b) 0.1, (c) 0.5, and (d) 0.6 compounds.
Temperature dependence of the magnetic entropy (ΔSm ) obtained from M(H) data at μ0ΔH = (a) 1 T and (b) 5 T for x = 0 to 0.7. Inset shows the variation of maximum magnetic entropy with magnetic field for all compositions.
Values of (a) ΔSm at Tc and (b) refrigerant capacity (RC) for μ0ΔH = 1, 2, and 5 T and (c) Tc as a function of composition x. (d) Normalized ΔSm versus T/Tc for different x.
Arrott plots (μ0 H/M vs. M 2) of isothermal magnetization. Inset shows isothermal (−ΔS m) vs M 2 curve of Sm0.1La0.6Sr0.3MnO3.
(a) Spontaneous magnetization and inverse initial susceptibility deduced by extrapolating Arrott plot (μ0 H/M vs. M 2) to μ0 H = 0 and M 2 = 0, respectively. Solid lines are best fits to the equations M s(T) = M 0| ε |β and χ0 −1 (T) = (h0 /M0 )εγ . (b) Spontaneous magnetization of Sm0.1La0.6Sr0.3MnO3 estimated from (−ΔS m) vs M 2 curve and Arrott plots.
Normalised ΔSm versus normalized temperature θ for different applied magnetic fields for Sm0.1La0.6Sr0.3MnO3.
Structural parameters calculated from X-ray diffraction data. BL is the average Mn-O bond length.
Ferromagnetic Curie temperature (TC ), activation energy (Eρ), maximum entropy change (ΔSm ), and refrigerant capacity (RC) for different compositions.
Magnetocaloric parameters at the Curie temperature TC for different manganites.
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