Structural and magnetic properties with large reversible magnetocaloric effect in (La1-xPrx)(0.85)Ag0.15MnO3 (0.0 <= x <= 0.5) compounds

Abstract

We report on the effect of Pr doping on structural, magnetic and magnetocaloric properties in (La1-xPrx)(0.85)Ag0.15MnO3 (0.0 <= x <= 0.5) compounds. The main crystal structure has been studied by performing X-ray diffraction method and structural analysis based on Rietveld method where it is found that although samples at low concentration level (x <= 0.2) have rhombohedral phase

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, others (x >= 0.3) have orthorhombic (Pbnm) phase. Scanning electron microscope images show that the average particle size decreases by increasing Pr amount in the main structure. It is observed that the second-order transition temperature from ferromagnetic to paramagnetic phase is dramatically decreased from 262 to 138K by increasing Pr concentration in (La1-xPrx)(0.85)Ag0.15MnO3. On the other hand, all samples have also antiferromagnetic coupling observed below T-N~50K. The maximum magnetic entropy change (-Delta S-M)(max) and relative cooling power values were found in the range of 7.90-2.88J/kgK and 213.32-153.50J/kg, respectively, under 50 kOe field change in our samples. It can be argued that particularly the compounds LPAM with x=0.0, 0.1 and 0.2 are expected to be promising candidate for magnetic refrigeration.