Magnetic and Microwave Properties of NiFe Nanowires Embedded in Anodized Aluminum Oxide (AAO) Templates

Ferromagnetic NiFe nanowire arrays were fabricated on porous alumina templates by an electrochemical method. The nanowires were controlled to have different diameter (100, 200 nm) and length (10, 20, 30 $\mu$m) in order to understand the magnetostatic interactions between nanowires. Through the control of geometry of the arrays, the magnetization direction was shown to change from parallel to perpendicular to wire direction. The anisotropy field of these arrays was measured much higher than 1 kOe, which resulted in excellent microwave properties, particularly for noise suppression properties over 10 GHz.