Ground-state ferrimagnetism and magneto-caloric effects in Nd₂NiMnO₆

Abstract

Abstract Extending our earlier investigation of magnetic properties of Nd 2 NiMnO 6 , we show that it exhibits a magnetic transition below ∼6 K to a ferrimagnetic state. This behavior is interpreted as arising from a long-range ordering of Nd moments antiferromagnetically coupled to the ferromagnetic Ni–Mn ordered moments. Due to the richness of its multiple magnetic transitions and the easily influenced magnetic state by the application of an external magnetic field, established in our earlier study, it has a remarkable inverse magneto-caloric effect (IMCE) at low temperatures (T &lt; 50 K) together with a significant conventional magneto-caloric effect (CMCE) at the ferromagnetic ordering temperature (T c ∼ 200 K). IMCE and CMCE correspond to the antiferromagnetic arrangement of Nd and Ni–Mn sublattices and ferromagnetic ordering of Ni–Mn sublattices, respectively. Nd 2 NiMnO 6 with its second order phase transition follows the universal behavior of ∆S M (T); it also shows a power law dependency on the magnetic field as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mrow> <mml:mi>S</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>M</mml:mi> <mml:mspace width=".25em"/> </mml:mrow> </mml:msub> <mml:mo>∝</mml:mo> <mml:msup> <mml:mrow> <mml:mi>H</mml:mi> </mml:mrow> <mml:mi>η</mml:mi> </mml:msup> <mml:mo>.</mml:mo> </mml:math>