Ab initio lattice dynamics of Ni2MnX (X = Sn, Sb) magnetic shape memory alloys
Küçük Resim Yok
Tarih
2012
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Sa
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
In this study, we present the results of first principles calculations of elastic constants and phonon properties of nickel-manganese based magnetic shape memory compounds Ni2MnSn and Ni2MnSb in stoichiometric composition. The plane wave basis sets and pseudopotential method within spin-polarized generalized gradient approximation (sigma-GGA) scheme of the density functional theory is applied. In investigation of the phonon dispersion spectra, linear response technique of the Density Functional Perturbation Theory is used. Phonon softening is observed in dispersion spectra at the transverse acoustic mode (TA(2)) in [zeta zeta 0] direction as an indication of the structural instability of these systems to shear deformation. The vibrational instability of Ni2MnSb system is larger than that of Ni2MnSn yielding negative phonon frequencies. This vibrational anomaly is also verified by the low shear modulus and large elastic anisotropy ratio. The minority spin Fermi surfaces of both systems exhibit strong nesting features. (C) 2011 Elsevier B. V. All rights reserved.
Açıklama
Anahtar Kelimeler
Magnetically ordered materials, Elasticity, Phonons, Computer simulations
Kaynak
Journal of Alloys and Compounds
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
511
Sayı
1
