Effect of Frustrated Exchange Interactions and Spin-half Impurity on the Electronic Structure of Strongly Correlated NiFeO
arXiv:1704.02454 · doi:10.1103/PhysRevB.96.035138
Abstract
Spin-polarized density functional calculations, magnetization, and neutron diffraction measurements are carried out to investigate the magnetic exchange interactions and strong correlation effects in Yb substituted inverse spinel nickel ferrite. In the pristine form, the compound is found to be a mixed insulator under the Zaanen-Sawtazsky-Allen classification scheme as it features both charge transfer and Mott insulator mechanism. Estimation of magnetic exchange couplings reveals that both octahedral-octahedral and octahedral-tetrahedral spin-spin interactions are antiferromagnetic which is typical of a spin-frustrated triangular lattice. However, the latter is dominant compared to the former leading to a forced parallel alignment of the spins at the octahedral site which is in agreement with the results of neutron diffraction measurements. The substituent Yb is found to be settled in +3 charge state, as confirmed from the XPS measurements, to behave like a spin-half impurity carried by the localized orbital. The impurity spin significantly weakens the antiferromagnetic coupling with the spins at the tetrahedral site, which explains the experimental observation of fall in Curie temperature with Yb substitution.
arXiv comment11 pages, 8 figures
References in corpus (6)
- Electronic structure of normal and inverse spinel ferrites from first principles
- Short-Range B-site Ordering in Inverse Spinel Ferrite NiFe2O4
- Epitaxial strain effects in the spinel ferrites CoFe2O4 and NiFe2O4 from first principles
- First-principles calculation of magnetoelastic coefficients and magnetostriction in the spinel ferrites CoFe2O4 and NiFe2O4
- Effect of epitaxial strain on the cation distribution in spinel ferrites CoFe2O4 and NiFe2O4: a density functional theory study
- Spin-filtering efficiency of ferrimagnetic spinels CoFe2O4 and NiFe2O4