Preparation And Dynamic Magnetic Properties Of Magnetic Metallic Nanostructures

Due to their unique properties and promising applications, magnetic metal nanostructures have attracted a lot of research interests in recent years. Based on micromagnetics and experiments, this work intends to investigate the dynamic properties of various metal nanostructures such as nanowire, nanotube and nanodot.To begin with, the dynamic magnetic spectra of single isolated nanowire, nanotube and nanodot are studied by means of OOMMF. Simulation results indicate that their magnetic spectra are a function of parameters such as diameter, length, saturation magnetization and magnetocrystalline anisotropy constant. In addition, it is revealed that magnetostatic interaction plays an important role in the dynamic properties of nanowire and nanodot arrays. Furthermore, nanowires with different aspect ratio or different saturation magnetization are combined for micromagnetic simulation.Then, various nanowires including Co, Ni, Ni/Co multilayered and CoNiCu alloy nanowires have been prepared within anodized alumina template by electrodeposition, and their morphology, crystal structure, static and dynamic magnetic properties are discussed. The hysterisis loops of all the nanowire arrays manifest little anisotropy. Nevertheless, experimental results suggest these magnetic nanowires as potential microwave absorbers in the GHz range, with light weight and strong absorption.Furthermore, NiP nanotubes were fabricated through electroless chemical deposition and CoNiCu/Cu multilayered nanotube were synthesized within alumina and polycarbonate template through electrodeposition. In comparison with nanowires, nanotubes show many different properties, such as multiple absorbing peaks and wide band absorption peaks in their reflection loss spectra.