Field dependence of magnetocaloric properties of 20% Cr-doped Pr0.7Ca0.3MnO3 perovskite

• Published in: Journal of thermal analysis and calorimetry 2017-07, Vol.129 (1), p.53-64
• Main Authors: M’nassri, R., Selmi, A., Boudjada, N. Chniba, Cheikhrouhou, A.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemical Sciences; Chemistry; Chemistry and Materials Science; Collapse; Cooling; Cristallography; Criteria; Diffraction; Doping; Entropy; Ferromagnetism; Inorganic Chemistry; Magnetic properties; Manganites; Measurement Science and Instrumentation; Phase transitions; Physical Chemistry; Polymer Sciences; S curves; Scaling laws; X-ray diffraction
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-017-6110-1

In this study, we have investigated the effect of 20% Cr doping at the Mn site on the magnetic and magnetocaloric properties of Pr 0.7 Ca 0.3 MnO 3 polycrystalline manganites elaborated using the solid-state reaction. The X-ray powder diffraction shows that compounds crystallize in the orthorhombic system with Pnma space group. The parent compound Pr 0.7 Ca 0.3 MnO 3 is a well-known charge-ordered (CO) compound. The selective substitution of Cr for Mn in the pristine compound destroys the CO ordering observed in Pr 0.7 Ca 0.3 MnO 3 , and a paramagnetic to ferromagnetic transition takes place. The field dependence of the magnetic entropy change ∆ S and of the relative cooling power RCP is reported. The Δ S max are found to be 0.8 and 2.87 J kg −1  K in a magnetic field change of 5 T for x  = 0 and 0.2, respectively. The RCP is found to be 253.2 J kg −1 in the Pr 0.7 Ca 0.3 Mn 0.8 Cr 0.2 O 3 at 5 T. With the scaling laws, the experimental ∆ S and n collapse onto a universal curve for Pr 0.7 Ca 0.3 Mn 0.8 Cr 0.2 O 3 sample, where an average curve is obtained for ∆ S . With the phenomenological universal curve, the magnetic entropy change ∆ S curves are well predicted for Cr-substituted sample. Additionally, Banerjee’s criteria, the universal behavior and Landau theory of phase transitions were also studied to assess magnetic ordering in the Pr 0.7 Ca 0.3 Mn 0.8 Cr 0.2 O 3 material.