Ab initio lattice dynamics of Ni2MnX (X=Sn, Sb) magnetic shape memory alloys

Ağduk, Savaş; Gökoğlu, Gökhan

doi:10.1016/j.jallcom.2011.08.092

Cited by 22 publications

(14 citation statements)

References 35 publications

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“…Figure 3 shows typical calculated vibrational densities of states (vDOS) of the austenite phase of Ni2MnSn, using both GGA (PBE) and LDA, from the direct method whose numerical procedure is described above. The perfect match of our PBE-estimated vDOS with the PBEpredicted one in the literature, determined from DFPT calculations [51], is worth noticing.…”

Section: Resultssupporting

confidence: 69%

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Determination of the vibrational contribution to the entropy change at the martensitic transformation in Ni–Mn–Sn metamagnetic shape memory alloys: a combined approach of time-of-flight neutron spectroscopy andab initiocalculations

Recarte

Zbiri

Jiménez‐Ruiz

et al. 2016

J. Phys.: Condens. Matter

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The different contributions to the entropy change linked to the austenite-martensitic transition in a Ni-Mn-Sn metamagnetic shape memory alloy have been determined by combining different experimental techniques. The vibrational contribution has been inferred from the vibrational density of states of both the martensitic and austenite phases. This has been accomplished by combining time-of-flight neutron scattering measurements and ab-initio calculations. Further, the electronic part of the entropy change has also been calculated. Since the martensitic transformation takes place between two paramagnetic phases, the magnetic contribution can be neglected and the entropy change can be reduced to the sum of two terms: vibrational and electronic. The obtained value of the vibrational contribution (−36 ± 5 J kg −1 K −1 ) nearly provides the total entropy change measured by calorimetry (−41 ± 3 J kg −1 K −1 ), the difference being the electronic contribution within the experimental error.3

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Section: Resultssupporting

confidence: 69%

“…Further, our LDA-based vDOS illustrates the expected volume effect of the exchangecorrelation in terms of the maximum energy transfer which in the case of LDA exceeds that from PBE calculations (~ 32 meV from LDA and ~ 28 meV from our PBE calculations and reference [51]). …”

Section: The Next Step Is To Infer G(e)mentioning

confidence: 58%

Determination of the vibrational contribution to the entropy change at the martensitic transformation in Ni–Mn–Sn metamagnetic shape memory alloys: a combined approach of time-of-flight neutron spectroscopy andab initiocalculations

Recarte

Zbiri

Jiménez‐Ruiz

et al. 2016

J. Phys.: Condens. Matter

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“…Such anomalies 320 have been known to have significant effects on the physical properties of materials. In some of the Heusler compounds such as Ni 2 MnGa [33,34], Ni 2 MnIn [35], Ni 2 MnX (X= Sn, Sb) [36], Ni 2 VAl and Ni 2 NbX (X=Al, Ga, Sn) [37], which all have a face-centred-cubic struc-325 ture like SnAs, the softening of the acoustic mode is a Kohn anomaly due to interaction of the conduction electrons with the lattice.…”

mentioning

confidence: 99%

Enhanced superconductivity in the high pressure phase of SnAs studied from first principles

Reddy

Kanchana

Millichamp³

et al. 2017

Physica B: Condensed Matter

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. AbstractFirst principles calculations are performed using density functional theory and density functional perturbation theory for SnAs. Total energy calculations show the first order phase transition from an NaCl structure to a CsCl one at around 37 GPa, which is also confirmed from enthalpy calculations and agrees well with experimental work. Calculations of the phonon structure and hence the electron-phonon coupling, λ ep , and superconducting transition temperature, T c , across the phase diagram are performed. These calculations give an ambient pressure T c , in the NaCl structure, of 3.08 K, in good agreement with experiment whilst at the transition pressure, in the CsCl structure, a drastically increased value of T c = 12.2 K is found. Calculations also show a dramatic increase in the electronic density of states at this pressure. The lowest energy acoustic phonon branch in each structure also demonstrates some softening effects. Electronic structure calculations of the Fermi surface in both phases are presented for the first time as well as further calculations of the generalised susceptibility with the inclusion of matrix elements. These calculations indicate that the softening is not derived from Fermi surface nesting and it is concluded to be due to a wavevector-dependent enhancement of the electron-phonon coupling.

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“…Examples among Heusler alloys are seen, where inspite of a soft phonon mode being found in the calculations, no MST has been observed [7]. We consider the example of compounds given by Ni 2 Mn 1+x Sn 1−x .…”

Section: Introductionmentioning

confidence: 99%

Driving force for martensitic transformation inNi2Mn1+xSn1−x

et al. 2016

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The martensitic transformation in Ni 2 Mn 1+x Sn 1−x alloys has been investigated within ab-initio density functional theory. The experimental trend of a martensitic transition happening beyond x = 0.36 is captured within these calculations. The microscopic considerations leading to this are traced to increased Ni-Mn hybridization which results from the Ni atom experiencing a resultant force along a lattice parameter and moving towards the Mn atoms above a critical concentration.The presence of the lone pair electrons on Sn forces the movement of Ni atoms away from Sn.While band Jahn Teller effects have been associated with this transition, we show quantitatively that atleast in this class of compounds they have a minor role.

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Ab initio lattice dynamics of Ni2MnX (X=Sn, Sb) magnetic shape memory alloys

Cited by 22 publications

References 35 publications

Determination of the vibrational contribution to the entropy change at the martensitic transformation in Ni–Mn–Sn metamagnetic shape memory alloys: a combined approach of time-of-flight neutron spectroscopy andab initiocalculations

Determination of the vibrational contribution to the entropy change at the martensitic transformation in Ni–Mn–Sn metamagnetic shape memory alloys: a combined approach of time-of-flight neutron spectroscopy andab initiocalculations

Enhanced superconductivity in the high pressure phase of SnAs studied from first principles

Driving force for martensitic transformation inNi2Mn1+xSn1−x

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