Exchange through nonmagnetic insulating matrix

Exchange through nonmagnetic insulating matrix

Investigation of weak interlayer exchange coupling in GaMnAs/GaAs superlattices with insulating nonmagnetic spacers

A robust long-range antiferromagnetic coupling between ferromagnetic Ga0.97Mn0.03As layers has previously been realized via insertion of nonmagnetic Be-doped GaAs spacers between the magnetic layers. In this paper we report the observation of weak antiferromagnetic coupling between Ga0.97Mn0.03As layers through undoped GaAs spacers with thicknesses as large as 25 monolayers. The field and the t...

Influence of ferromagnetic substrate on the magnetoresistance of Cr film across a nonmagnetic insulating layer

~5 nm! Cr/(x nm) MgO/Mn0.52Zn0.48Fe2O4 ~MnZn spinel! substrate (1,x,7 nm), as well as ~5 nm! Cr/~7 nm! MgO/glass substrate structures have been grown using molecular beam epitaxy. The influence of the MnZn spinel on the in-plane transport and magnetotransport properties of the Cr layer were studied. The existence of pinholes in the MgO layer was explored by evaluating resistance versus temperat...

Insulating ground States of transition-metal monoxides from exact exchange.

The exact exchange of density functional theory is used to calculate the electronic structure of the antiferromagnetic (type II) phases of the transition-metal monoxides MnO, FeO, CoO, and NiO at T=0. In contrast with the local density approximation (LDA) and generalized gradient approximation, the exact exchange (combined with LDA correlation) correctly yields insulating ground states for all ...

Order-N implementation of exact exchange in extended insulating systems

Exact Hartree-Fock exchange is needed to overcome some of the limitations of local and semilocal approximations of density-functional theory. So far, however, computational cost has limited the use of exact exchange in plane-wave calculations for extended systems. We show that this difficulty can be overcome by performing a unitary transformation from Bloch to maximally localized Wannier functi...