Magnetization reversal, critical behavior, and magnetocaloric effect in NdMnO3: The role of magnetic ordering of Nd and Mn moments

The magnetic properties, critical behavior, and magnetocaloric effect of perovskite NdMnO3 are studied. The Nd ordering is induced by the Mn ferromagnetic component with antiferromagnetic coupling with each other and then magnetization reversal occurs due to Mn moments reorientation induced by the ordering Nd moments, which explains the phenomenon of negative magnetization at low temperatures. The critical behavior of NdMnO3 is studied using Kouvel-Fisher and self-consistent methods. The results show that the Kouvel-Fisher method is reliable and critical exponents are coming out as beta = 0.462 for T-C = 11.15 K, gamma = 1.041 for T-C = 11.42 K, delta = 3.252 by critical isotherm analysis. Magnetic exchange distance may decay as J ( r ) & AP; r - 4.563, that is, somewhere between the three-dimensional Heisenberg model and the mean field model. Remarkably, three temperature transitions and the corresponding three extremum values including positive and negative entropy change are observed in NdMnO3, which is different from previous reports on NdMnO3. A positive entropy change as 3.82 J/kg K at 10-15 K for mu(0)& UDelta;H = 50 kOe and a negative entropy change as -0.557 J/kg K at around 8 K for mu(0)& UDelta;H = 5 kOe are found, which can be put down to a fast magnetization change of NdMnO3 because of the Nd moments ordering and Mn moments reorientation. Besides, an entropy change of 1.22 J/kg K is found for mu(0)& UDelta;H = 50 kOe at 80-85 K, which is corresponding to the Mn ferromagnetic ordering temperature. The relative cooling power of NdMnO3 reaches 105.9 J/kg, making it a promising candidate in the field of magnetic refrigeration. Published under an exclusive license by AIP Publishing.

Automated summary

The magnetic properties, critical behavior, and magnetocaloric effect of perovskite NdMnO3 are studied. The ordering of Nd induced by the ferromagnetic Mn component with antiferromagnetic coupling leads to magnetization reversal and negative magnetization at low temperatures. The critical behavior of NdMnO3 is analyzed using Kouvel-Fisher and self-consistent methods, and the results show that the Kouvel-Fisher method is reliable. Remarkably, three temperature transitions and corresponding extremum values, including positive and negative entropy change, are observed in NdMnO3.