Short-range antiferromagnetic correlations and large magnetic entropy change in (La0.5Pr0.5)0.67Ca0.33MnO3

We report a detailed study of magnetic properties in manganite (La0.5Pr0.5)(0.67)Ca0.33MnO3. In contrast to the usual beliefs, it shows an abnormal upturn deviation from the Curie-Weiss law on the inverse susceptibility curve. Such a non-Griffiths-like phase is further confirmed from the inverse double integrated intensities of electron paramagnetic resonance spectrum. Because La ions are substituted by Pr ions with 50% concentrations, the ratio of three ions (La, Pr, Ca) is close to 1 on A-site sublattice. As a result, some short-range antiferromagnetic (CO AFM) phases come into being in the system due to the existence of localized charge ordering states. Therefore, the upturn deviation from Curie-Weiss law originates from the appearance of short-range CO AFM correlations above . Additionally, a magnetic field-driven-metamagnetic transition is found, which gives a main contribution for the large magnetic entropy change (MEC) observed in this sample. Both the Arrott plot and the renormalized MEC curves testify that this transition belongs to first-order magnetic transition. The insignificant hysteresis loop indicate that the inevitable thermal hysteresis can be ignored in the present first-order material implying that it is a potential candidate for the cryogenic temperature magnetic refrigeration.