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arXiv · 1508.00087

Giant magnetocaloric effect in Gd2NiMnO6 and Gd2CoMnO6 ferromagnetic insulators

J. Krishna Murthy·K. Devi Chandrasekhar·Sudipta Mahana·D. Topwal·A. Venimadhav
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Abstract

We have investigated magnetocaloric effect in double perovskite Gd2NiMnO6 (GNMO) and Gd2CoMnO6 (GCMO) samples by magnetic and heat capacity measurements. Ferromagnetic ordering is observed at ~130 K (~112 K) in GNMO (GCMO), while the Gd exchange interactions seem to dominate for T < 20 K. In GCMO, below 50 K, an antiferromagnetic behaviour due to 3d-4f exchnage interaction is observed. A maximum entropy (-ΔSM) and adiabatic temperature change of ~35.5 J Kg-1 K-1 (~24 J Kg-1 K-1) and 10.5 K (6.5 K) is observed in GNMO (GCMO) for a magnetic field change of 7 T at low temperatures. Absence of magnetic and thermal hysteresis and their insulating nature make them promising for low temperature magnetic refrigeration.

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J. Krishna Murthy, K. Devi Chandrasekhar, Sudipta Mahana, D. Topwal, A. Venimadhav. 2015-08-01. Giant magnetocaloric effect in Gd2NiMnO6 and Gd2CoMnO6 ferromagnetic insulators. https://doi.org/10.1088/0022-3727%2F48%2F35%2F355001

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