Magnetic ordering of the martensite phase in Ni–Co–Mn–Sn-based ferromagnetic shape memory alloys. (10th December 2019)

• Record Type: Journal Article
• Authors: Sarkar, Sudip Kumar; Ahlawat, Sarita; Kaushik, S D; Babu, P D; Sen, Debasis; Honecker, Dirk; Biswas, Aniruddha
• Is Part Of: Journal of physics. Volume 32:Number 11(2020)
• Publication Date: 2019-12-10
• Subjects: FSMAs -- Ni–Co–Mn–Sn alloys -- anti-ferromagnetism -- superparamagnetism -- spin glass -- small angle neutron scattering; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ab5876
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The magnetic state of low temperature martensite phase in Co-substituted Ni–Mn–Sn-based ferromagnetic shape memory alloys (FSMAs) has been investigated, in view of numerous conflicting reports of occurrences of spin glass (SG), superparamagnetism (SPM) or long range anti-ferromagnetic (AF) ordering. Combination of DC magnetization, AC susceptibility and small angle neutron scattering (SANS) studies provide clear evidence for AF order in the martensitic phase of Ni45 Co5 Mn38 Sn12 alloy and rule out SPM and SG orders. Identical studies on another alloy of close composition, Ni44 Co6 Mn40 Sn10, point to the presence of SG order in the martensitic phase and the absence of SPM behavior, contrary to earlier reports. SANS results do show the presence of nanometre-sized clusters but they are found to grow in size from 3 nm at 30 K to 11 nm at 300 K, and do not correlate with magnetism in these alloys.