Optimization of the FeCo nanowire fabrication embedded in anodic aluminum oxide template by response surface methodology

Abstract

Anodic aluminum oxide (AAO) fabricated by two step anodization technique, is used as a template to synthesize FeCo nanowire arrays by AC electrodeposition technique. Response surface methodology (RSM) is applied to design the experiments, fit an empirical model and optimize the conditions to achieve the best magnetic properties. The magnetic properties, pore dimensions, composition and structure of the nanowires are characterized through alternating gradient force magnetometer (AGFM), scanning electron microscopy (SEM), scanning probe microscopy (SPM), energy dispersive spectoroscopy (EDS) and X-ray diffraction (XRD), respectively. The effects of annealing temperature (T_a), Fe concentration (C), the pH of the deposition solution (pH) and electrodeposition temperature (T_d) on the magnetic properties are investigated. Maximum experimental coercivity field (H_c = 191.4 KA/m) is obtained in the following conditions: T_a = 550 °C; C = 50 wt%; pH = 6; T_d = 40 °C. The optimum values to obtain maximum predicted coercivity field (H_c = 195.5 KA/m) are predicted with a statistical technique as: T_a = 575 °C; C = 50.3 wt%; pH = 6; T_d = 39 °C. Moreover, the results show that T_d² and T_a are the most important parameters affecting coercivity field. XRD results show that the crystal structure of nanowires is BCC with (1 1 0) preferred orientation along the nanowire axis.