Mossbauer and Magneto Caloric Effect for La0.7Ca0.3Mn0.9957Fe0.01O3

The crystallographic and magneto caloric effects of La0.7Ca0.3Mn0.99 (Fe0.01O3)-Fe-57 powders were studied by using X-ray diffraction, vibrating sample magnetometer, and Mossbauer spectroscopy. To investigate the effect of sintering conditions on LCMO, the samples were sintered in air and evacuated sealed quartz tube. The calculated magnetic entropy change in the magnetic fields of 1.5 T for the samples which sintered in air and evacuated sealed quartz tube are 1.6 J/kg K and 3.2 J/kg K, respectively. The temperatures of the maximum slope in dM/dT for the samples which sintered in air and evacuated sealed quartz tube are 242 K and 262 K, respectively. For the explanation of the Mossbauer line broadening, we applied the presence the fluctuating magnetic field, which jumps between the values of hyperfine field, +H and -H, along the z-axis with a frequency f. We calculated anisotropy energy from Mossbauer relaxation analysis.