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 ...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.展开更多
Co nanowire arrays of different crystal struc-tures have been electrodeposited into self-assembled anodic aluminum oxide (AAO) templates by varying pH value of electrolyte. The XRD results show that crystal structure ...Co nanowire arrays of different crystal struc-tures have been electrodeposited into self-assembled anodic aluminum oxide (AAO) templates by varying pH value of electrolyte. The XRD results show that crystal structure of Co nanowires is fcc structure at pH = 2.5, a mixed structure of fcc and hcp at pH = 3.0 and 3.5, and hcp structure at pH = 5.0. Magnetic measurements indicate that Co nanowire ar-rays of different crystal structures exhibit different magnetic properties. The coercivity of Co nanowire array of fcc struc-ture is larger than that of hcp structure about 900×103/4p A·m-1 along wire axis, and its squareness is also larger than that of hcp structure.展开更多
基金Project(6067655) supported by the National Natural Science Foundation of ChinaProject(2005CB623605) supported by the National Basic Research Program of China+1 种基金Project(E0320002) supported by the Natural Science Foundation of Fujian Province, ChinaProject(JB07045) supported by the Educational Department of Fujian Province, China
文摘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.
文摘Co nanowire arrays of different crystal struc-tures have been electrodeposited into self-assembled anodic aluminum oxide (AAO) templates by varying pH value of electrolyte. The XRD results show that crystal structure of Co nanowires is fcc structure at pH = 2.5, a mixed structure of fcc and hcp at pH = 3.0 and 3.5, and hcp structure at pH = 5.0. Magnetic measurements indicate that Co nanowire ar-rays of different crystal structures exhibit different magnetic properties. The coercivity of Co nanowire array of fcc struc-ture is larger than that of hcp structure about 900×103/4p A·m-1 along wire axis, and its squareness is also larger than that of hcp structure.
