Surface and Bulk Magnetization Behavior of Isolated Ferromagnetic NiFe Nanowires

Authors: Musaab Salman Sultan

Abstract:

The surface and bulk magnetization behavior of template released isolated ferromagnetic Ni₆₀Fe₄₀ nanowires of relatively thick diameters (~200 nm), deposited from a dilute suspension onto pre-patterned insulating chips have been investigated experimentally, using a highly sensitive Magneto-Optical Ker Effect (MOKE) magnetometry and Magneto-Resistance (MR) measurements, respectively. The MR data were consistent with the theoretical predictions of the anisotropic magneto-resistance (AMR) effect. The MR measurements, in all the angles of investigations, showed large features and a series of nonmonotonic "continuous small features" in the resistance profiles. The extracted switching fields from these features and from MOKE loops were compared with each other and with the switching fields reported in the literature that adopted the same analytical techniques on the similar compositions and dimensions of nanowires. A large difference between MOKE and MR measurments was noticed. The disparate between MOKE and MR results is attributed to the variance in the micro-magnetic structure of the surface and the bulk of such ferromagnetic nanowires. This result was ascertained using micro-magnetic simulations on an individual: cylindrical and rectangular cross sections NiFe nanowires, with the same diameter/thickness of the experimental wires, using the Object Oriented Micro-magnetic Framework (OOMMF) package where the simulated loops showed different switching events, indicating that such wires have different magnetic states in the reversal process and the micro-magnetic spin structures during switching behavior was complicated. These results further supported the difference between surface and bulk magnetization behavior in these nanowires. This work suggests that a combination of MOKE and MR measurements is required to fully understand the magnetization behavior of such relatively thick isolated cylindrical ferromagnetic nanowires.

Keywords: MOKE magnetometry, MR measurements, OOMMF package, micro-magnetic simulations, ferromagnetic nanowires, surface magnetic properties.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1474395

References:

[1] Sun, L., Hao, Y., Chien, C.-L. & Searson, P. C. "Tuning the properties of magnetic nanowires" IBM J. Res. Devel., 49(1), 79, 2005.
[2] Asli, E., Surendra, N., Tewari, & Orhan Talu. "Electrodeposition of nickel nanowires and nanotubes using various templates" J. Exp. Nanosc., 3, 4, 287, 2008.
[3] Lupu, N. "Electrodeposited nanowires and their applications" Intech., India, 2010.
[4] Rahman, I. Z., Razeeb, K. M., Kamruzzaman, Md., & Serantoni, M. "Characterisation of electrodeposited Ni nanowires using NCA template" J. Mats. Proc. Tech., 153-154, 811, 2004.
[5] Liu, R. S., Chang, S. C., Baginskiy, I., Hu, S. F., & Huang, C. Y. "Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu nanowires" Pramana, 67(1), 85, 2006.
[6] Lupu, N., Lostun, M. & Chiriac, H. "Surface magnetization processes in soft magnetic nanowires" J. Appl. Phys., 107(9), 09E315, 2010.
[7] Sultan, Musaab S. "Angular dependence of switching behaviour in template released isolated NiFe nanowires" Phys. Lett. A, 381, 46, 3896, 2017.
[8] Vila, L., George, J. M., Faini, G., Popa, A., Ebels, U., Ounadjela, K. & Piraux, L. "Transport and magnetic properties of isolated cobalt nanowires" IEEE Trans. Mag., 38(5), 2577, 2002.
[9] Rheem, Y., Yoo, B.-Y., Beyermann, W. P. & Myung, N. V. "Magneto-transport studies of single ferromagnetic nanowire" Phys. Stat. Sol. (a), 204(12), 4004, 2007.
[10] Rheem, Y., Yoo, B.-Y., Beyermann, W. P. & Myung, N. V. "Electro-and magneto-transport properties of a single CoNi nanowire" Nanotech., 18(12), 125204, 2007.
[11] Sultan, M. S., Atkinson, D. "Aspect-ratio dependence of magnetization reversal in cylindrical ferromagnetic nanowires" Material Research Express, 3, 056104, 2016.
[12] Sultan, Musaab S., "Electro and magneto transport behavior of template released isolated ferromagnetic nanowires" IEEE Trans. Mag., 53, 12, 1, 2017. DOI: 10.1109/TMAG.2017.2740848.