Quantitative magnetic force microscopy analysis of the magnetization process in nanowire arrays

Abstract

Magnetic force microscopy (MFM) imaging is a useful technique to locally study the magnetic state of nanostructures. In this paper, we have used the MFM to characterize an ordered array of Ni nanowires embedded in porous membrane. Due to the large aspect ratio of the wires (30 nm diameter and 1000 nm length) they present an axial easy axis. Considering the nanowires as nearly single-domain structures and calculating the amount of wires pointing to each direction, we can obtain the average magnetization. An alternative method to analyze the MFM data is here introduced considering the distribution functions of magnetic contrast. By using this method, the magnetization process of the nanowire array is studied and the results are compared with major and minor hysteresis loops measured by superconducting quantum interference device magnetometer.