Impacts of nanostructuring and magnetic ordering of Nd3+ on the magnetic and magnetocaloric response in NdMnO3

• DOI: 10.1016/j.jmmm.2015.02.032
• Publication Date: 2015-02-17T00:46:51Z
• Authors: Sayan Chandra; Anis Biswas; Manh-Huong Phan; Hariharan Srikanth
• Keywords: Magnetic refrigeration; Nanocrystalline material

Abstract Magnetocaloric properties of NdMnO3 were investigated in its bulk polycrystalline and nanocrystalline forms. The nanocrystalline sample (average particle size ∼40 nm) exhibits a maximum in the temperature dependence of magnetic entropy change [−ΔSM(T)] at ∼70 K due to the paramagnetic to ferromagnetic transition, which is absent in case of its bulk counterpart. The absence of peak in −ΔSM(T) in the bulk sample is attributed to the co-existence of antiferromagnetic and ferromagnetic phases. A canted magnetic state (CMS) is stabilized at low temperature for both the samples due to the ordering of Nd3+ giving rise to a peak in −ΔSM(T) at ∼15 K. Interestingly −ΔSM(T) for these two samples show a universal behavior near their transitions at low temperature although their temperature dependence of magnetization is markedly different around those transitions. A detailed analysis of magnetocaloric data conclusively establishes the existence of a canted magnetic state, which is not obvious from magnetometry, demonstrating the usefulness of this method for probing phase coexistence and multiple magnetic states in complex oxide systems.