Local atomic arrangement and martensitic transformation in Ni50Mn35In15: an EXAFS study

Bhobe, P. A.; Priolkar, K. R.; Sarode, P. R.

doi:10.1088/0022-3727/41/4/045004

Cited by 22 publications

(10 citation statements)

References 25 publications

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“…The outcome of such investigation presents new evidence for the crucial hybridization component that influences and leads to structural transitions in Ni-Mn based SMA. The inferences drawn from this work have been found to be robust and validated through experiments like photoemission spectroscopy by others 9,10 , and in other SMA like Ni-Mn-In and Ni-MnSn series by us [11][12][13] ; here we present the case study of Ni-Mn-Ga series alone.…”

Section: Ni-mn-ga Shape Memory Alloyssupporting

confidence: 73%

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Bhobe

2017

Current Science

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Over the last few decades, there has been growing interest for developing technologies aimed at providing cleaner and more sustainable energy sources. Great efforts are directed towards synthesis of newer functional materials and tailoring the existing ones with an aim to optimize their usability. As materials are being developed with various complexities in their physical properties and forms like single crystals, thin-films, nanostructure and composites, measurement of their basic physical properties is also getting equally challenging. This review deals with a brief summary of our efforts in developing the basic understanding of some functional materials, using experimental tools that are best known to us, viz. measurement of Seebeck coefficient and X-ray absorption fine structure spectroscopy (XAFS). In particular, we discuss the results of our investigation of magnetic shape memory alloy Ni 2 MnGa and multiferroic CdCr 2 Se 4 . Keywords: Magnetic shape memory alloys, XAFS, thermopower measurements, spin-phonon coupling, magnetic semiconductors. IntroductionTHE present age research in materials science is largely focussed around providing alternative technologies aimed at cleaner and more sustainable energy sources. Hence the mention of thermoelectric power in the perspective of contemporary research generally implies new schemes for materials synthesis and device fabrication with enhanced performance. This article, however, focusses on thermopower and XAFS measurements as an investigative tool, used for understanding material properties, not limited to thermoelectrics. What is thermoelectric power?In most simple terms, thermoelectric power or thermoelectricity is all about generating electrical power from heat, using a solid-state device without combustion or moving parts. It is an effect that involves interplay between electrical and thermal properties of a material with electrons acting as the active fluid. The two primary physical phenomena that are at play in thermoelectrics are the Seebeck effect and the Peltier effect.Discovered in 1821 by T. J. Seebeck and hence named after him, this effect describes how a temperature gradient (T) across a conductor leads to electric charge flow, causing a measureable potential gradient (V) across it. Thus, V = ST, where S is the Seebeck coefficient. The opposite effect, i.e. generation of temperature gradient upon passage of electric current (I) through a conductor was discovered by J. Peltier. The expression for heat absorbed/emitted being, Q = I, where  is the Peltier coefficient. It was not until 1855, when W. Thomson (Lord Kelvin), using thermodynamics laws, showed that the Seebeck and Peltier effects are basically inter-linked. He also pointed out the need for the third effect to be considered, which is reversible heating or cooling when there is both a flow of electric current and a temperature gradient.Thus was the birth of a concept -a type of heat engine that could be used either as a device for generating electricity from heat or, alternatively, as a h...

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Section: Ni-mn-ga Shape Memory Alloyssupporting

confidence: 73%

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Bhobe

2017

Current Science

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“…The ordered crystal structure in such Mn rich composition contains excess Mn atoms at the In site in addition to its regular ( 1 4 , 1 4 , 1 4 ) sites. We have previously studied the local crystal structure of these systems in the cubic and martensitic phase and obtained the exact interatomic separation between constituent atoms in both the phases [26]. In the cubic phase, Ni 50 Mn 35 In 15 has a lattice parameters of ∼ 6.04Å .…”

Section: Resultsmentioning

confidence: 99%

Anomalous magnetic properties in Ni₅₀Mn₃₅In₁₅

Bhobe¹,

Priolkar²,

Nigam³

2008

J. Phys. D: Appl. Phys.

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Abstract. We present here a comprehensive investigation of the magnetic ordering in Ni 50 Mn 35 In 15 composition. A concomitant first order martensitic transition and the magnetic ordering occurring in this off-stoichiometric Heusler compound at room temperature signifies the multifunctional character of this magnetic shape memory alloy. Unusual features are observed in the dependence of the magnetization on temperature that can be ascribed to a frustrated magnetic order. It is compelling to ascribe these features to the cluster type description that may arise due to inhomogeneity in the distribution of magnetic atoms. However, evidences are presented from our ac susceptibility, electrical resistivity and dc magnetization studies that there exists a competing ferromagnetic and antiferromagnetic order within crystal structure of this system. We show that excess Mn atoms that substitute the In atoms have a crucial bearing on the magnetic order of this compound. These excess Mn atoms are antiferromagnetically aligned to the other Mn, which explains the peculiar dependence of magnetization on temperature.Submitted to: J. Phys. D: Appl. Phys.

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“…With further cooling the magnetisation continued to increase, resulting in a splitting of the magnetisation state between the cooling and the heating curves of the martensite. This splitting is attributed to the existence of exchange bias effect in martensite at low temperatures [24,25,35,36]. As discussed earlier, the distance between Mn at Mn site and Mn at Sn site is small enough to introduce antiferromagnetic exchange between each other.…”

Section: Magnetic Propertiesmentioning

confidence: 95%

Metallurgical origin of the effect of Fe doping on the martensitic and magnetic transformation behaviours of Ni50Mn40-xSn10Fex magnetic shape memory alloys

Wu¹,

Liu²,

Yang³

et al. 2011

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Local atomic arrangement and martensitic transformation in Ni₅₀Mn₃₅In₁₅: an EXAFS study

Cited by 22 publications

References 25 publications

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Anomalous magnetic properties in Ni₅₀Mn₃₅In₁₅

Metallurgical origin of the effect of Fe doping on the martensitic and magnetic transformation behaviours of Ni50Mn40-xSn10Fex magnetic shape memory alloys

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Local atomic arrangement and martensitic transformation in Ni50Mn35In15: an EXAFS study

Cited by 22 publications

References 25 publications

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Peek into the World of Materials Using Thermopower and Xafs as Investigative Probes

Anomalous magnetic properties in Ni50Mn35In15

Metallurgical origin of the effect of Fe doping on the martensitic and magnetic transformation behaviours of Ni50Mn40-xSn10Fex magnetic shape memory alloys

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Product

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About

Local atomic arrangement and martensitic transformation in Ni₅₀Mn₃₅In₁₅: an EXAFS study

Anomalous magnetic properties in Ni₅₀Mn₃₅In₁₅