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The electronic structure and magnetism in fayalites M2SiO4 (M=Fe and Co) have been studied by density functional theory within the generalized gradient approximation with the on-site Coulomb energy taken into account (GGA+U). Stable insulating antiferromagnetic solutions are obtained. It is found that the gap opening in these fayalites results mainly from strong on-site Coulomb interactions of the magnetic atoms. In the band structures, the conduction bands originate mainly from the M(3d) orbitals of M2SiO4. The top of valence bands consists of the Fe (3d) orbitals in Fe2SiO4, and of the Co(3d)–O(2p) hybridization in Co2SiO4. All calculated orbital magnetic moments are very small. [Copyright &y& Elsevier]

First-principles density functional calculations of the total energy, magnetic moments and magnetocrystalline anisotropy energy (MAE) of CrO2 as a function of both volume and uniaxial strain along the c-axis have been performed. The highly accurate all-electron full-potential linearized augmented plane wave method and the generalized gradient approximation to the exchange–correlation potential are used. The calculated structural properties (lattice constants and unit cell volume) are in excellent agreement with experiments (with 0.5%). The calculated bulk and Young’s modulii are 2.56 and 2.02 Mbar, respectively. The calculated MAE increases almost linearly with the uniaxial strain and remains positive in the strain range of -4–4%. Thus, the calculations predict that the easy magnetization axis is along the c-axis, in agreement with experiments. However, the calculated anisotropy constant is about six times larger than the measured value. The calculated magnetoelastic coupling constant is 1.2×107 erg/cm3 and the magnetostriction coefficient λ001 is -2.59×10-5. [Copyright &y& Elsevier]

We haved calculated the magnetic moments and magnetic anisotropy energy (MAE) of the ordered Fe0.5Pd0.5 alloy by using relativistic linear muffin-tin orbital and full-potential linear augmented plane wave methods and also including the orbital polarization correction (OPC) and the generalized gradiant approximation. The OPC substantially increases the Fe orbital moments in the alloy, thereby reducing the discrepancy between the measured and theoretical orbital moments. For all the lattice parameters considered, the [0 0 1] direction is found to be the easy axis, thus showing no spin-reorientation transition as suggested recently. The calculated MAE agrees with experiments. [Copyright &y& Elsevier]

We present a spin-density-functional theoretical (SDFT) study of the electronic states in GaAs quantum dots embedded in AlGaAs substrates. The SDFT allows for a systematic study of the joint effects of confinement, Coulomb interactions and spin for realistic systems. We model the system as electrons confined in a finite cylindrical dot. The screening due to the gate electrodes is also taken into account. The method predicts the electron addition energy spectra that are in agreement with experiments. We also apply the SDFT to GaAs quantum rings and find that they too show shell structures in the additional energy spectra. [Copyright &y& Elsevier]

The magnetocrystalline anisotropy energy of CoFe2O4 under uniaxial strain along [0 0 1] direction has been studied by using the linear muffin-tin orbital method within the density functional theory. The calculated uniaxial anisotropy constant Kout is positive for extensive in-plane (0 0 1) strains and is negative for compressive in-plane strains. The positive value of Kout indicates that a CoFe2O4 film under an extensive in-plane strain would show the out-of-plane [0 0 1] magnetization. [Copyright &y& Elsevier]

The electronic structure, mechanical and magnetic properties of Ni3Al, Ni3Ga and Ni3In have been studied by spin-density functional theory with generalized gradient approximation and also by X-ray absorption near-edge spectra (XANES) at the Ni, Ga K edges. The calculated lattice constants and bulk modulii are in good agreement with experiments. All three compounds have a similar calculated density of states (DOS) spectrum and are predicted to be a weak ferromagnet. The measured Ni(Ga) K-edge XANES are well explained by the theoretical XANES and unoccupied Ni(Ga)-p DOS, suggesting that XANES is a useful probe of the electronic structure of the intermetallics. [Copyright &y& Elsevier]

Ferromagnetism in 3d transition metal-atom-doped ZnO was investigated by ab initio electronic structure calculations based on the generalized gradient approximation (GGA). We also performed GGA+U calculations to further refine our results. We found that Mn-doped ZnO has the largest magnetic moment and Sc-doped ZnO is nonmagnetic. Also, Mn- Co- or Cu-doped ZnO are ferromagnetic semiconductors. For the other 3d transition metal atoms the doped ZnO are metals. The appearance of ferromagnetism in these systems suggests the possibility for fabrication of a transparent ferromagnet which may have a great impact on industrial applications in magneto-optical devices. [Copyright &y& Elsevier]