Elastic inconsistency of the force constant models for body centred tetragonal indium

Ramamurthy, V.; Rajendraprasad, S.

doi:10.1016/0022-3697(86)90142-3

Cited by 6 publications

(3 citation statements)

References 20 publications

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“…[15][16][17] However, for some of the alloys, this correlation fails. It has been argued that the volume of the alloys may also be important when tracing T M .…”

Section: Magnetic Momentsmentioning

confidence: 99%

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Site preference and elastic properties of Fe-, Co-, and Cu-doped Ni2MnGa shape memory alloys from first principles

Luo

et al. 2011

Phys. Rev. B

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The site preference and elastic properties of Fe-, Co-, and Cu-doped Ni 2 MnGa alloys are investigated by using the first-principles exact muffin-tin orbital method in combination with coherent-potential approximation. It is shown that Fe atom prefers to occupy the Mn and Ni sublattices even in Ga-deficient alloys; Co has strong tendency to occupy the Ni sublattice in all types of alloys; Cu atoms always occupy the sublattice of the host elements in deficiency. For most of the alloys with stable site occupations, both the electron density n and the shear modulus C can be considered as predictors of the composition dependence of the martensitic transition temperature T M of the alloys. The physics underlying the composition-dependent C are discussed based on the calculated density of states.

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“…[15][16][17] However, for some of the alloys, this correlation fails. It has been argued that the volume of the alloys may also be important when tracing T M .…”

Section: Magnetic Momentsmentioning

confidence: 99%

“…[15][16][17] This correlation provides a predictor for the composition-dependent T M of Ni 2 MnGa-based alloys. However, such a correlation breaks down for the Fe-doped Ni 2 MnGa alloys.…”

Section: Introductionmentioning

confidence: 99%

Site preference and elastic properties of Fe-, Co-, and Cu-doped Ni2MnGa shape memory alloys from first principles

Luo

et al. 2011

Phys. Rev. B

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“…However, they offer very interesting perspectives, both for fundamental understanding as well as for engineering materials with target properties. The number of valence electron per atom(e/a) was identified to be a predictor of T m with T m ∼ e/a [33][34][35] for systems undergoing martensitic transformations. In case of offstoichiometric Ni 2 MnGa alloys and Fe, Co and Cu substituted Ni 2 MnGa alloys e/a was found not to correlate with T m .…”

Section: Introductionmentioning

confidence: 99%

Effect of Fe and Co substitution on the martensitic stability and the elastic, electronic, and magnetic properties ofMn2NiGa: Insights fromab initiocalculations

Kundu

Ghosh

2017

Phys. Rev. B

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We investigate the effects of Fe and Co substitutions on the phase stability of the martensitic phase, mechanical, electronic and magnetic properties of magnetic shape memory system Mn2NiGa by first-principles Density functional theory(DFT) calculations. The evolution of these aspects upon substitution of Fe and Co at different crystallographic sites are investigated by computing the electronic structure, mechanical properties (tetragonal shear constant, Pugh ratio and Cauchy pressure) and magnetic exchange parameters. We find that the martensitic phase of Mn2NiGa gradually de-stabilises with increase in concentration of Fe/Co due to the weakening of the minority spin hybridisation of Ni and Mn atoms occupying crystallographically equivalent sites. The interplay between relative structural stability and the compositional changes are understood from the variations in the elastic modulii and electronic structures. We find that like in the Ni2MnGa-based systems, the elastic shear modulus C can be considered as a predictor of composition dependence of martensitic transformation temperature Tm in substituted Mn2NiGa, thus singling it out as the universally acceptable predictor for martensitic transformation in Ni-Mn-Ga compounds over a wide composition range. The magnetic properties of Mn2NiGa are found to be greatly improved by the substitutions due to stronger ferromagnetic interactions in the compounds. The gradually weaker(stronger) Jahn-Teller distortion (covalent bonding) in the minority spin densities of states due to substitutions lead to a half-metallic like gap in these compounds resulting in materials with high spin-polarisation when the substitutions are complete. The substitutions at the Ga site result in two new compounds Mn2NiFe and Mn2NiCo with very high magnetic moments and Curie temperatures. Thus, our work indicates that although the substitutions de-stabilise the martensitic phase in Mn2NiGa, new magnetic materials with very good magnetic parameters and potentially useful for novel magnetic applications can be obtained. This can trigger interests in the experimental community for further research on substituted Mn2NiGa.

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Consequences of crystallographic equivalence between bct and fct indium

Ramamurthy

1986

Phys. Rev. B

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Elastic inconsistency of the force constant models for body centred tetragonal indium

Cited by 6 publications

References 20 publications

Site preference and elastic properties of Fe-, Co-, and Cu-doped Ni2MnGa shape memory alloys from first principles

Site preference and elastic properties of Fe-, Co-, and Cu-doped Ni2MnGa shape memory alloys from first principles

Effect of Fe and Co substitution on the martensitic stability and the elastic, electronic, and magnetic properties ofMn2NiGa: Insights fromab initiocalculations

Consequences of crystallographic equivalence between bct and fct indium

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