Competition between cubic and tetragonal phases in all-d-metal Heusler alloys, X2−xMn1+xV (X = Pd, Ni, Pt, Ag, Au, Ir, Co; x = 1, 0): a new potential direction of the Heusler family

IUCrJ

卷:6

Zhenxiang Cheng¹  Tingting Lin²  Rabah Khenata³  Xiaotian Wang⁴  Yilin Han⁴  Tie Yang⁴  Mengxin Wu⁴  Yu Feng⁵ 

[1] Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong 2500, Australia;

[2] Institute of Materials Science, Technische Universtät Darmstadt, Darmstadt 64287, Germany;

[3] Laboratoire de Physique Quantique de la Matière et de Modélisation Mathématique (LPQ3M), Université de Mascara, Mascara 29000, Algeria;

[4] School of Physical Science and Technology, Southwest University, Chongqing 400715, People's Republic of China;

[5] School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, People's Republic of China;

关键词: all-d-metal Heusler alloys;    tetragonal deformation;    computational modelling;    density functional theory;   

DOI  :  10.1107/S2052252519004007

来源: DOAJ

【 摘 要 】

In this work, a series of all-d-metal Heusler alloys, X2 − xMn1 + xV (X = Pd, Ni, Pt, Ag, Au, Ir, Co; x; = 1, 0), were predicted by first principles. The series can be roughly divided into two categories: XMn2V (Mn-rich type) and X2MnV (Mn-poor type). Using optimized structural analysis, it is shown that the ground state of these all-d-metal Heusler alloys does not fully meet the site-preference rule for classic full-Heusler alloys. All the Mn-rich type alloys tend to form the L21 structure, where the two Mn atoms prefer to occupy the A (0, 0, 0) and C (0.5, 0.5, 0.5) Wyckoff sites, whereas for the Mn-poor-type alloys, some are stable with XA structures and some are not. The c/a ratio was also changed while maintaining the volume the same as in the cubic state to investigate the possible tetragonal transformation of these alloys. The Mn-rich Heusler alloys have strong cubic resistance; however, all the Mn-poor alloys prefer to have a tetragonal state instead of a cubic phase through tetragonal transformations. The origin of the tetragonal state and the competition between the cubic and tetragonal phases in Mn-poor alloys are discussed in detail. Results show that broader and shallower density-of-states structures at or in the vicinity of the Fermi level lower the total energy and stabilize the tetragonal phases of X2MnV (X = Pd, Ni, Pt, Ag, Au, Ir, Co). Furthermore, the lack of virtual frequency in the phonon spectra confirms the stability of the tetragonal states of these Mn-poor all-d-metal Heusler alloys. This work provides relevant experimental guidance in the search for possible martensitic Heusler alloys in all-d-metal materials with less Mn and new spintronic and magnetic intelligent materials among all-d-metal Heusler alloys.

【 授权许可】

Unknown