Abstract
Magnetic Heusler compounds (MHCs) have recently attracted great attention since these types of material provide novel functionalities in spintronic and magneto-electronic devices. Among the MHCs, some compounds have been predicted to be spin-filter semiconductors [also called magnetic semiconductors (MSs)], spin-gapless semiconductors (SGSs) or half-metals (HMs). In this work, by means of first-principles calculations, it is demonstrated that rare earth-based equiatomic quaternary Heusler (EQH) compounds with the formula MCoVZ (M = Lu, Y; Z = Si, Ge) are new spin-filter semiconductors with total magnetic moments of 3 µB. Furthermore, under uniform strain, there are physical transitions from spin-filter semiconductor (MS) → SGS → HM for EQH compounds with the formula LuCoVZ, and from HM → SGS → MS → SGS → HM for EQH compounds with the formula YCoVZ. Remarkably, for YCoVZ EQH compounds there are not only diverse physical transitions, but also different types of spin-gapless feature that can be observed with changing lattice constants. The structural stability of these four EQH compounds is also examined from the points of view of formation energy, cohesive energy and mechanical behaviour. This work is likely to inspire consideration of rare earth-based EQH compounds for application in future spintronic and magneto-electronic devices.
Highlights
In the areas of materials science and solid-state chemistry and physics (Zuticet al., 2004; Wolf et al, 2001), neither spintronics nor magneto-electronics can be ignored
Electronic structure and the Slater–Pauling rule In Table 2, we have given the calculated equilibrium lattice constants, the total and individual atomic magnetic moments, and the number of valence electrons for these four equiatomic quaternary Heusler (EQH) compounds with the type III structure
The LuCoVZ and YCoVZ compounds undergo interesting physics, changing from magnetic semiconductors (MSs) ! spin-gapless semiconductors (SGSs) ! HM and HM ! SGS ! MS ! SGS ! HM, respectively, which means that the electronic and magnetic structures could be extensively tuned by external temperature or pressure
Summary
In the areas of materials science and solid-state chemistry and physics (Zuticet al., 2004; Wolf et al, 2001), neither spintronics nor magneto-electronics can be ignored. In 2013, CoVTiAl and CrVTiAl EQH compounds were identified as MSs by Ozdogan and co-workers (Galanakis et al, 2013; Galanakis, Ozdogan et al, 2014) According to their theoretical results, CoVTiAl and CrVTiAl present high Curie temperatures, making these materials suitable for roomtemperature spintronics and magneto-electronics applications. Bainsla, Kharel and co-workers have successfully prepared samples of CoFeMnSi (Bainsla, Mallick et al, 2014) and MnCrVAl (Kharel, 2017) EQH-based SGSs. In this work, to ensure the suitability of CASTEP for EQHbased SGSs with relatively subtle band structures, the electronic structures of these two EQH compounds were first calculated using the CASTEP code. For all the rare earth-containing EQH compounds, type III (see Fig. 1c) is the most stable because it has the lowest energy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
