Density-functional description of spinelZnFe2O4

Abstract

Density-functional calculations of electronic and magnetic properties of the spinel compound ZnFe 2 O 4 done with the general potential linearized augmented plane-wave method are reported. We find significant differences between local spin-density approximation and generalized gradient approximation calculations. In the generalized gradient approximation an insulating antiferromagnetic state is found, leaving open the question of the role of Hubbard correlations in this material. The results are discussed in view of existing experimental data.

Electronic Structure and Bulk Spin-Valve Behavior inCa3Ru2O7

“…This includes robust itinerant ferromagnetism (SrRuO 3 ) 1,2 , paramagnetic "bad" metals (CaRuO 3 ) 3 , unconventional superconductivity (Sr 2 RuO 4 ) 4 , an antiferromagnetic (AFM) Mott insulator (Ca 2 RuO 4 ) 5 , and metamagnetic quantum critical behavior (Sr 3 Ru 2 O 7 ) 6 . This reflects exceptionally strong dependence of electronic and magnetic properties on lattice degrees of freedom, also seen in band structure studies 7,8,9,10 .…”

“…However, for the AFM case, the majority and minority spin lie on top of each other due to the alternating spin up and spin down bi-layers.The spin magnetization with FM ordering is 1.934 µ B /Ru, of which only 1.23 µ B is within the Ru LAPW sphere (radius 2.05 a 0 ). The remaining ∼ 1/3 is O in character, comparable to other FM ruthenates8,9 . The origin is the strong Ru-O hybridization in these 4d com-pounds, combined with Hund's coupling on O.…”

Effects of Fe substitution on the electronic, transport, and magnetic properties of ZnGa2O4: A systematic ab initio study

“…4 we find thus a zero-temperature insulator with a band gap of 0.4 eV. It is interesting to compare this band gap with that of the end compound ZnFe 2 O 4 where within GGA it is calculated to be one order of magnitude less 24 . This can be ascribed to the direct cation-cation bonding in the case of ZnFe 2 O 4 .…”

Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott SystemCa3Ru2O7

“…Small changes in the tilting can result in qualitative changes in the properties. Local density approximation calculations for Sr 3 Ru 2 O 7 , which has common aspects with Ca 3 Ru 2 O 7 , find the Fermi surface very sensitive to small structural changes which readily shift the Fermi energy [1].…”