The electronic structure and optical properties of Zn1-x BexO alloys were studied using first principle calculation based on density functional theory （DTF）. The results indicate that the band gap of Zn1-x BexO alloys increases as Be composition increases. The major reason is that the valence band maximum （VBM） of O2p has no obvious shift while the conduction band minimum （CBM） of Zn4s shifts to higher energy as x composition increases. Calculated results of the imaginary part of the dielectric function reveal that the peak heights at 2.0 and 6.76eV decrease as x composition increases, which is attributed to the decrease of the Zn3d states after Be substitutes for Zn. Due to the increasing transition probability from VBM of O2p to CBM of Be2s in wurtzite structure BeO,the peak height at 9.9eV is enhanced and its position shifts toward higher energy.
Based on Monte Carlo method, the hysteresis loops for both individual Co nanowires and their array were simulated, and the influence of the strength of the dipolar interaction on the macroscopical magnetic properties of Co nanowire array was investigated. The simulated results indicate that the coercivity approximately increases linearly with the increase of the strength coefficient of the dipolar interaction. The interwire dipole interaction between wires tends to develop a magnetic easy axis perpendicular to the wire axis. In the magnetic reversal process, competition between the interwire dipolar interaction and the shape anisotropy of individual wires which forces the moments to orient along the axis makes the magnetic reversal of the array different from that of individual wire. For applied field parallel to wire axis, the coercivity of nanowire array increases rapidly with the increase of the nearest-neighbor interwire distance, and approximately increases linearly with the increase of the strength coefficient of the dipolar interaction for the fixed diameter and the nearest-neighbor interwire distance. While for applied field perpendicular to wire axis, in contrast, the coercivity decreases with increasing the nearest-neighbor interwire distance, and nearly remains a constant with the increase of the strength coefficient of the dipolar interaction.
