Surface Morphology and Magnetic Properties of Isolated Cylindrical Nickel Nanowires

Abstract

Abstract:In this article, the surface morphology and magnetic properties of isolated cylindrical nickel (Ni) nanowires fabricated by electrodeposition have been thoroughly investigated using scanning electron microscopy and Magneto-Optical Kerr Effect (MOKE) magnetometry, respectively. The surfaces of most nanowires were found to be homogenous, uniform, and cylindrical in shape. Some others show different diameters and surface features, including; protrusions and branches along their length. The diameter distribution of a wide range of nanowires was found to differ from their template pore diameters. These all variations are more likely due to defects exist in the internal surfaces of the pores within the template itself, or may be associated with the trapped air pockets within the pores during nanowires growth or due to the oxide formation or residual contaminants which may cover these wires. The nanowires lengths were found to differ from their actual lengths estimated during deposition growth. This was attributed to the breakage of nanowires into small sections during releasing process. The hysteresis loops obtained by applying a magnetic field at different angles with respect to the nanowires long axis showed square hysteresis loops with a sharp jump of Kerr signal during switching behaviour, as well as a high squareness ratio, indicating the dominance of shape anisotropy. These results are quite different from the measurements of high density templated nanowires reported in the literature, due to the small number of nearest neighbour nanowires, and hence no magneto-static interaction. The magnetisation reversal of such wires is well described by the non-uniform rotation of the curling model of domain reversal.

Magnetic and Electrical Properties of Electrodeposited Nickel Films

“…Now, to gain a fuller understanding of the magnetic properties of such films, the coercivity acquired here was compared with other results reported in the literature discussing isolated Ni and NiFe nanowires prepared under the same conditions and measured also by MOKE magnetometry (Sultan, et al, 2012;Sultan, 2017a;2017b;2018), a large difference was noticed. This large difference is quite acceptable since the crystallites within such ferromagnetic thin films have no preferred orientations and have no shape anisotropy dominating the behavior as in the nanowires.…”

“…Once the electrodeposition was finished, the chips were washed thoroughly in distilled water, followed by IPA, and blown with argon gas. Further, information on the deposition procedure using this technique can be found in (Das, et al, 2008;Possin, 1970;Sultan, et al, 2012;Sultan, 2017a;2017b;2018). Now, to analyze the elemental composition of these samples, energy-dispersive X-ray spectroscopy (EDS) analysis on the Hitachi-SU 70 was used.…”

“…The obtained hysteresis loops were the reflected Kerr light against the externally applied magnetic field. More theoretical (Brundle, Evans and Wilson, 1992;Cullity and Graham, 2009;Jiles, 1998) and experimental (Eastwood, 2009;Lupu, Lostun and Chiriac, 2010;Sultan, et al, 2012;Sultan, 2017a;2017b;2018) details on the MOKE setup and its measurements can be found elsewhere.…”

“…The magnetic properties of such ferromagnetic thin films were also investigated using a range of characterization systems, which include superconducting quantum interference device, vibrating sample magnetometry, torque http://dx.doi.org/10.14500/aro.11211 magnetometry, and alternating gradient magnetometry, as well as magnetic force microscopy. On the other hand, the Magneto-Optical Kerr Effect (MOKE) setup has also been used to demonstrate the magnetization behavior of a range of magnetic thin films (Azzawi, et al, 2016;Ganguly, et al, 2015;Michelini, et al, 2002), nanodots (Heyderman, et al, 2004), nanowires (Allwood, et al, 2003;Bryan, Atkinson and Allwood, 2006;Maruyama, et al, 1997), and more complex geometric shapes of nanostructures (Chen, et al, 2010;Das, et al, 2016;Eider, et al, 2016;Ester, et al, 2015;Lupu, Lostun and Chiriac, 2010;Philip, et al, 2016;Sharma, et al, 2009;Sultan, et al, 2012;Sultan, 2017aSultan, , 2017b2018;Vega, et al, 2012). However, in this setup, the reflected light is proportional to the amount of magnetization within the surface of the film, which depends on the polarization rotation of a polarized laser light following its reflection from a ferromagnetic sample to the skin depth (Allwood, et al, 2003).…”

Angular Dependence of Magnetization Behavior in Ni81Fe19 Nanowires by Micromagnetic Simulations

“…Te magnetic properties of ferromagnetic nanostructures have been experimentally discovered using a wide range of characterization systems, including alternating gradient magnetometer (AGM), vibrating sample magnetometer (VSM), torque magnetometry (TM), superconducting quantum interference device (SQID), and atomic/magnetic force microscopy [17][18][19][20][21][22][23]. On the other hand, the magnetization behavior of isolated (individual) nanowires has been analyzed using micro-SQUID, electromagneto-transport measurements [30][31][32][33][34][35][36], and magnetooptical Kerr efect (MOKE) magnetometry [37][38][39][40][41][42].…”