Giant magnetocaloric effect in Gd2NiMnO6 and Gd2CoMnO6 ferromagnetic insulators. (10th August 2015)

• Record Type: Journal Article
• Authors: Krishna Murthy, J; Devi Chandrasekhar, K; Mahana, Sudipta; Topwal, D; Venimadhav, A
• Is Part Of: Journal of physics. Volume 48:Number 35(2015)
• Publication Date: 2015-08-10
• Subjects: magnetocaloric -- double perovskites -- magnetic oxides; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/48/35/355001
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We have investigated the magnetocaloric effect in double perovskite Gd2 NiMnO6 (GNMO) and Gd2 CoMnO6 (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, antiferromagnetic behaviour due to the 3d–4f negative exchange interaction is observed. A maximum entropy (−Δ S M ) 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.