We present a temperature-dependent atomic and magnetic pair distribution function (PDF) analysis of neutron total scattering measurements of antiferromagnetic MnO, an archetypal strongly correlated transition-metal oxide. The known antiferromagnetic ground-state structure fits the low-temperature data closely with refined parameters that agree with conventional techniques, confirming the reliab...

In compounds La1/3Ca2/3MnO3 and BiMnO3, a calculation of spin-wave dispersion dependences along pseudoperovskite directions reciprocal space is made. The model includes orbitally dependent superexchange interaction single-ion anisotropy. Considered present competing exchange interactions within magnetic unit cell because orbital or charge-orbital ordering. nearest neighbor taken into account. s...

We derive a spin-orbital Hamiltonian for a triangular lattice of eg orbital degenerate (Ni) transition metal ions interacting via 90 superexchange involving (O) anions, taking into account the on-site Coulomb interactions on both the anions and the transition metal ions. The derived interactions in the spin-orbital model are strongly frustrated, with the strongest orbital interactions selecting...

We present a simple model to study the electron doped manganese perovskites. The model considers the competition between double exchange mechanism for itinerant electrons and antiferromagnetic superexchange interaction for localized electrons. It represents each Mn ion by a spin 1/2, on which an electron can be added to produce Mn; we include a hopping energy t, a strong intratomic ferromagneti...

Mossbauer spectra of MnFez04 with various particle sizes in a longitudinal 50 kOe magnetic field show that the Fe ion occupancy of the A and B crystallographic sites depends on the particle size. The elevated N6el temperatures with decreasing particle sizes are attributed to an increased iron occupancy on the A sites; this in turn leads to an increase in the total superexchange interaction.