Temperature dependent magnetic, dielectric and Raman studies of partially disordered La2NiMnO6

Kumar, Pradeep and Ghara, Somnath and Rajeswaran, B and Muthu, DVS and Sundaresan, A and Sood, AK (2014) Temperature dependent magnetic, dielectric and Raman studies of partially disordered La2NiMnO6. In: SOLID STATE COMMUNICATIONS, 184 . pp. 47-51.

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Abstract

We report a detailed magnetic, dielectric and Raman studies on partially disordered and biphasic double perovskite La2NiMnO6. DC and AC magnetic susceptibility measurements show two magnetic anomalies at T-C1 similar to 270 K and T-C2 similar to 240 K, which may indicate the ferromagnetic ordering of the monoclinic and rhombohedral phases, respectively. A broad peak at a lower temperature (T-sg similar to 70 K) is also observed indicating a spin-glass transition due to partial anti-site disorder of Ni2+ and Mn4+ ions. Unlike the pure monoclinic phase, the biphasic compound exhibits a broad but a clear dielectric anomaly around 270 K which is a signature of magneto-dielectric effect. Temperature-dependent Raman studies between the temperature range 12-300 K in a wide spectral range from 220 cm(-1) to 1530 cm(-1) reveal a strong renormalization of the first as well as second-order Raman modes associated with the (Ni/Mn)O-6 octahedra near T-C1 implying a strong spin-phonon coupling. In addition, an anomaly is seen in the vicinity of spin-glass transition temperature in the temperature dependence of the frequency of the anti-symmetric stretching vibration of the octahedra. (C) 2014 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	SOLID STATE COMMUNICATIONS
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copyright for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, ENGLAND
Keywords:	Spin-phonon coupling
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 May 2014 05:14
Last Modified:	22 May 2014 05:14
URI:	http://eprints.iisc.ac.in/id/eprint/48975

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