Predictions on structural, electronic, magnetic and thermal properties of new Heusler alloys Cr $$_{{{2}}}$$
- PDF / 1,488,647 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 23 Downloads / 290 Views
© Indian Academy of Sciences
Predictions on structural, electronic, magnetic and thermal properties of new Heusler alloys Cr2 NbSi1−x Ge x from first-principles calculations I ASFOUR Département de Technologie des Matériaux, Faculté de Physique, Université des Sciences et de la Technologie d’Oran Mohamed Boudiaf (USTO-MB), BP 1505, El M’naouer, 31000 Oran, Algeria E-mail: [email protected], [email protected] MS received 12 May 2020; revised 8 July 2020; accepted 7 August 2020 Abstract. In this study, by using full-potential linearised augmented plane wave (FP-LAPW) method with the generalised gradient approximation (GGA) based on density functional theory (DFT), the structural, electronic, elastic and magnetic properties of the Heusler alloys Cr2 NbSi1−x Gex have been evaluated. The AlCu2 Mnl-type structure is more stable than the CuHg2 Ti-type structure at equilibrium volume for the compounds. The ground-state properties of our alloys including the lattice parameter and bulk modulus were calculated. In view of Poisson’s and Pugh’s ratio, the ductility and brittleness of Cr2 NbSi1−x Gex has been analysed. The mechanical stability is maintained throughout the pressure range with high value of Debye temperature. The electronic band structures and density of states of our compounds show a half metallic character with total magnetic moments, −3.00 μB per formula unit with indirect band gap, E g = 0.152 eV and 0.262 eV for Cr2 NbSi and Cr2 NbGe respectively. Furthermore, we have analysed the thermal properties by the quasi-harmonic Debye model. Through the obtained results, we can say that these compounds can be strong candidates for future spintronic applications. Keywords. Density functional theory investigations; quaternary Heusler alloys; electronic structure; gap; magnetic properties. Pacs Nos 60; 70
1. Introduction In solid-state physics, Heusler compounds have the largest variety of physical properties. Much research has been done by the electronic structure calculations of Groot, who predicted half-metallicity with ferromagnetic nature (HMF) for the first time in NiMnSb Heusler compound. Due to its potential application in spintronics devices, extensive research has been conducted on HMFs over the past decade [1]. Half-metallic ferromagnetism is one of the most important properties exhibited by this family, which is being exploited for various spintronics-related applications. This is mainly because of their large spin polarisation owing to their peculiar band structure and high magnetic ordering temperatures, compared to other known half-metallic ferromagnetic materials. This motivated many researchers to study these materials [2]. The Heusler alloys exhibit met-
0123456789().: V,-vol
alic behaviour for a spin band and a semiconductor behaviour for the other. They are either ferromagnetic or ferrimagnetic and at Fermi level spin polarisation is 100% [3–10]. The Heusler alloys made of transition metals and sp elements are promising candidates for potential spin injection applications because they have
Data Loading...
