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Title: Investigations on Ni-Co-Mn-Sn thin films: Effect of substrate temperature and Ar gas pressure on the martensitic transformations and exchange bias properties

We report the effect of substrate temperature (T{sub S}) and Ar gas pressure (P{sub D}) on the martensitic transformations, magnetic and exchange bias (EB) properties in Heusler type Ni-Co-Mn-Sn epitaxial thin films. Martensitic transformation temperatures and EB fields at 5 K were found to increase with increasing T{sub S}. The observed maximum EB value of 320 Oe after field cooling in the film deposited at 650 {sup ∘}C is high among the values reported for Ni-Mn-Sn thin films which is attributed to the coexistence of ferromagnetic (FM) and antiferromagnetic (AF) phases in the martensitic state. In the case of P{sub D} variation, with increase in P{sub D}, martensitic transformation temperatures were increased and a sharp transformation was observed in the film deposited at 0.06 mbar. Magnetization values at 5 K were higher for increasing P{sub D}. These observations are attributed to the compositional shift. EB effect is also present in these films. Microstructural features observed using atomic force microscopy (AFM) shows a fine twinning and reduced precipitation with increase in P{sub D}, which is also confirmed from the scanning electron microscopy (SEM) images. EB effects in both series were confirmed from the training effect. Target ageing effect has been observedmore » in the films deposited before and after ninety days of time interval. This has been confirmed both on substrate temperature and Ar gas pressure variations.« less
Authors:
;  [1]
  1. Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, D-55128 Mainz (Germany)
Publication Date:
OSTI Identifier:
22454469
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 3; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIFERROMAGNETISM; ATOMIC FORCE MICROSCOPY; DEPOSITS; EPITAXY; IMAGES; MAGNETIZATION; MARTENSITIC STEELS; MICROSTRUCTURE; PHASE TRANSFORMATIONS; SCANNING ELECTRON MICROSCOPY; THIN FILMS