Development of bi-axial preferred orientation in epitaxial NiMnGa thin films and its consequence on magnetic properties

Sharma, Amit and Mohan, S and Suwas, Satyam (2016) Development of bi-axial preferred orientation in epitaxial NiMnGa thin films and its consequence on magnetic properties. In: ACTA MATERIALIA, 113 . pp. 259-271.

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Abstract

In the present work, the crystal structure, the micro-structure and the crystallographic orientation of NiMnGa thin films fabricated on a Si (100) substrate using magnetron sputtering at elevated temperatures have been evaluated. X-ray diffraction based measurements confirm both in-plane and out of plane (bi-axial) alignment of the unit cells in the films. Three levels of hierarchy in the microstructure, and the presence of, primary nano-twinned martensitic variants and secondary nano-twins within the primary nano-twins due to adaptive modulation are some of the important microstructural features observed in the films using a transmission electron microscope. The results of temperature-dependent magnetization measurements and in-situ high temperature X-ray diffraction experiments indicate the presence of a pre-martensite phase above room temperature. Low temperature X-ray diffraction measurements reveal the evolution of a non-modulated (NM) martensite phase at 123 K. High resolution scanning electron microscopy (FE-SEM) and high resolution X-ray diffraction measurements have been carried out for an in-depth examination of the microstructure, growth morphology and crystalline quality of the films. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	ACTA MATERIALIA
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Keywords:	NiMnGa thin film; Magnetron sputtering; Bi-axial preferred orientation; Adaptive martensite; Pre-martensite phase; Magnetic properties
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	24 Aug 2016 09:26
Last Modified:	24 Aug 2016 09:26
URI:	http://eprints.iisc.ac.in/id/eprint/54318

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