A new range of specific perovskite-type materials with structural, magnetic and magnetocaloric properties: La0.67Ca0.33-xSrxMn0.98Fe0.02O3 (0.15 ≤ x ≤ 0.3)

The effect of strontium doping on the structural, magnetic and magnetocaloric properties of La(0.67)Ca(0.33-x)Sr(x)Wn(0.98)Fe(0.02)O(3) samples for (x = 0.15; 0.2.and 0.3) has been investigated. Analysis using X-ray diffraction shows there is an orthorhombic structure with Pnma space group symmetry for x = 0.15 compound, whereas there is a rhombohedral structure exhibiting R (3) over barc space group symmetry found for x = 0.2, and x = 0.3 compounds. A second-order magnetic phase transition from ferromagnetic to paramagnetic state transition is evidenced for all samples, with Curie temperature (T-C) values equal to 329 K, 330 K and 350 K and that respectively for x = 0.15, 0.2 and 0.3. Based on isothermal magnetization measurements versus applied magnetic field at several temperatures around T-C, the magnetic entropy change was calculated, which is very close to that approximated by the Landau theory for.x = 0.15. Under an applied magnetic field of 5 T, one can see the maximum magnetic entropy change (-Delta S-M(max)) values, which are around 4.89, 4.71 and 3.35 J.kg(-1).K-1 for x = 0.15, 0.2, and 0.3 respectively. It confirms that close to room temperature, these manganites are admirably potential functional materials, which can be applied as solid state magnetic refrigerants.