ABSTRACT

Heusler compounds exhibit a wide range of properties for both fundamental and potential technological interests. The extensive tunability of the Heusler compounds, through chemical substitutions and structural motifs, makes the family specifically interesting. As the maturity of these materials grows and commercial applications become more near-term, the properties of these materials become an important factor to both their processing and their final use. Here, we have investigated elasto-mechanical, transport and thermodynamics of Co₂XAl (X = Zr, Nb, Hf) Heuslers. The exchange correlation potentials are figured out by GGA, GGA + U_eff and GGA + mBJ methods to obtain more precise results of these materials. The continuity in the P–V plot indicates the absence of any structural phase transition from highly symmetric cubic structure to other structural phase. The magnetic interactions were taken into consideration, among which ferromagnetic configuration was found to be stable. The calculated elastic parameters recommend that these alloys are mechanically stable and possess ductile character. The efficient transport parameters with half-metallic and ductile nature suggest the likelihood applications of these alloys to design hard spintronic devices or potential thermoelectric materials. Furthermore, the high temperature and pressure variation of thermodynamic properties were calculated using the quasi-harmonic Debye approximation to descript its stability.

摘要

Heusler 化合物具有广泛的特性，可满足基本和潜在的技术利益。Heusler 化合物的广泛可调性，通过化学取代和结构基序，使这个家族特别有趣。随着这些材料的成熟度和商业应用的临近，这些材料的特性成为影响其加工和最终用途的重要因素。在这里，我们研究了 Co ₂ XAl (X = Zr, Nb, Hf) Heusler 的弹性力学、输运和热力学。通过 GGA、GGA + U _eff和 GGA + mBJ 方法计算交换相关势 以获得这些材料的更精确结果。P – V的连续性图表明不存在从高度对称的立方结构到其他结构相的任何结构相变。考虑了磁相互作用，发现其中铁磁构型是稳定的。计算出的弹性参数表明这些合金具有机械稳定性并具有延展性。具有半金属和延展性的有效传输参数表明这些合金可能应用于设计硬自旋电子器件或潜在的热电材料。此外，使用准谐波德拜近似计算热力学性质的高温和高压变化以描述其稳定性。