四元Heusler合金Co<sub>2</sub>V1-xCrxAl的电子结构、磁性及半金属性研究

戴晨盼; 卢志红; 刘静; 方孙; 程朝阳

文章摘要

四元Heusler合金Co₂V1-xCrxAl的电子结构、磁性及半金属性研究

Electronic structure, magnetic properties and half metallicity of quaternary Heusler alloys Co₂V1-xCrxAl

投稿时间：2017-01-09

DOI：

中文关键词: Heusler合金 Cr掺杂磁性半金属性费米面态密度四方变形

英文关键词: Heusler alloy Cr doping magnetism half-metallicity Fermi level density of state tetragonal distortion

基金项目:国家自然科学基金资助项目(11574242).

作者	单位	E-mail
戴晨盼	武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉,430081	dai-chenpan@foxmail.com
卢志红	武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉,430081
刘静	武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉,430081
方孙	武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉,430081
程朝阳	武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉,430081

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中文摘要:

利用第一性原理计算方法,研究了L2₁型Heusler合金Co₂V1-xCrxAl(x=0、0.25、0.5、0.75、1)的磁性、电子结构、半金属性及四方变形等。结果表明,随着Cr掺杂浓度的提高,合金总磁矩主要由Co的d电子贡献,总磁矩线性升高,符合Slater-Pauling规则,晶格常数线性减小,符合Vegard定律；此外,随着x的增加,费米面从临近导带底向靠近价带顶移动,能隙宽度增加,当x＞0.25时, 合金具有半金属性。Co₂V0.5Cr0.5Al合金由于费米面位于自旋向下带带隙中部,抗原子无序能力强,在整个合金系列中半金属稳定性最佳,且在四方变形研究中,当c/a在0.92~1.07范围内时,该合金仍能保持稳定的半金属性。

英文摘要:

The electronic structure, magnetism, half metallicity and tetragonal distortion of L2₁ type Heusler alloy Co₂V1-xCrxAl(x=0,0.25,0.5,0.75,1) were investigated using first principle method. The results show that total magnetic moments of the alloy, which are mainly contributed by the d electrons of Co atom, increase linearly with the increase of Cr doping concentration, whereas the lattice constants decrease linearly, according with the Slater-Pauling rule and Vegard’s law, respectively. Moreover, with the increase of x, the Fermi level moves from the bottom of conduction band to near the top of valence band and the width of energy gap also increases. The Heusler alloy exihibits half-metallicity even when x goes down to 0.5. Since the Fermi level lies in the middle of spin-down energy gap, Co₂V0.5Cr0.5Al alloy can withstand slight atomic disorder and exhibits an excellent half-metallic stability. Besides, in the research of its tetragonal distortion, Co₂V0.5Cr0.5Al alloy still presents a perfect half-metallicity as the tetragonality c/a varies from 0.92 to 1.07.

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