Correlation between microstructure and first-order-reversal-curve of Co nanowire arrays

Self-ordered Co nanowire arrays with different diameters of 30, 70 and 75 nm were grown into the anodized aluminum oxide templates by variation of deposition current between 5 and 55 mA. Increasing diameter of the nanowires enhances interaction between the nanowires, thereby decreasing the coercivity. However, increasing the deposition current decreases coercivity due to increase in deposition of light hydrogen ions. The microstructure investigations by x-ray diffraction patterns revealed that varying the diameter of deposited nanowires at constant current caused variation of preferential crystalline growth of the polycrystalline nanowires. Comparing first-order reversal curve (FORC) diagrams of the samples with different diameters and deposition currents revealed magnetization contribution of each FORC feature is proportional with a certain crystalline direction. Magnetic moment contribution of the domains with low and high coercivity and along the H=0 axis is correlated with intensity of Co (100), (110), (002) and (101), respectively.