| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1608516 | Journal of Alloys and Compounds | 2015 | 8 Pages |
•No structural changes are observed for FeMo, MoFe, Fe–Mo, VSr cases.•The 6 (8) nearest O neighbors move away from (close to) VFe or VMo (VO) vacancy.•Half-metal maintains for FeMo, VFe, VO, VSr, but vanishes for MoFe, Fe–Mo, VMo cases.•Spin moment of FeMo (MoFe) is antiferromagnetic coupling with that of regular site Fe (Mo).•Total moments decrease in sequence of VSr, VMo, VO, VFe, FeMo, MoFe, Fe–Mo.
From the point of view of the half-metallic character and magnetization reduction, the structural, electronic and magnetic properties of the imperfect Sr2FeMoO6 compound containing seven different defects of the FeMo or MoFe antisites, Fe–Mo interchange, VFe, VMo, VO or VSr vacancies have been studied by using first-principles projector augmented wave (PAW) within generalized gradient approximation (GGA) as well as taking into account on-site Coulomb repulsive interaction (GGA + U). No obvious structural changes are observed for the imperfect Sr2FeMoO6 compound containing FeMo or MoFe antisites, Fe–Mo interchange or VSr vacancy defects. However, the six (eight) nearest oxygen neighbors of the vacancy move away from (close to) VFe or VMo (VO) vacancies. The half-metallic character is maintained for the imperfect Sr2FeMoO6 compound containing FeMo antisite, VFe, VO or VSr vacancies, while it vanishes when MoFe antisite, Fe–Mo interchange or VMo vacancy are presented. So the MoFe antisite, Fe–Mo interchange or VMo vacancy defects have to be avoided in order to preserve the half-metallic character of the Sr2FeMoO6 compound and thus usable in spintronics devices. In FeMo or MoFe antisites, Fe–Mo interchange cases, the spin moments of Fe (Mo) cations situated on Mo (Fe) antisites are in an antiferromagnetic coupling with those of Fe (Mo) cations on the regular sites. In VFe, VMo, VO or VSr vacancies cases, a ferromagnetic coupling is obtained within each cation sublattice, while two cation sublattices are coupled antiferromagnetically. The total magnetic moments μtot (μB/f.u.) of the imperfect Sr2FeMoO6 compound containing seven different defects decrease in the sequence of VSr vacancy (4.38), VMo vacancy (3.92), VO vacancy (3.51), VFe vacancy (3.40), FeMo antisite (3.40), MoFe antisite (3.33), Fe–Mo interchange (2.47) and the mechanisms of the saturation magnetization reduction have been discussed.
Graphical abstractThe difference or spin charge density of four f.u. Sr2FeMoO6 containing seven different defects of (a) Fe antisite (FeMo) at (0.5, 0.5, 0.5) site, (b) Mo antisite (MoFe) at (0, 0.5, 0.5) site, (c) Fe–Mo interchange (Fe–Mo) at (0, 0, 0) and (0, 0, 0.5) sites, (d) Fe vacancy (VFe) at (0, 0.5, 0.5) site, (e) Mo vacancy (VMo) at (0.5, 0.5, 0.5) site, (f) O vacancy (VO) at (0.5, 0.5, 0.25) site, and (g) Sr vacancy (VSr) at (0.75, 0.75, 0.75) site. The yellow (turquoise) isosurfaces represent positive (negative) charge density of 0.0045/Å3 and thus up-spin (down-spin) moment. In the (100) cross sections, the colors blue, turquoise and green represent the value of charge density in increasing order.Figure optionsDownload full-size imageDownload as PowerPoint slide
