Thermally Activated Magnetic Switching Mode for Various Thicknesses of Perpendicularly Ferromagnetic Nano-dot

Author(s): Nur A. Wibowo*, Cahya Handoyo, Leopoldus R. Sasongko.

Journal Name: Nanoscience & Nanotechnology-Asia

Volume 9 , Issue 2 , 2019

Become EABM
Become Reviewer

Graphical Abstract:


Abstract:

Background: Even applying thermal pulse has been succeeded to reduce the coercivity through randomization the magnetization in such a way stimulate the magnetic reversion, the efficiency of magnetic switching field consumption in writing process still turns out to be an exciting research field to implement the HAMR technology. One of the remarkable geometric properties of HAMR storage media that can be correlated to the writing field reduction issue is the nano-dot thickness. Furthermore, thermal fluctuation causes the magnetization switching process to be probabilistic. This magnetic switching probability determines the magnitude of the writing field. This paper aims to investigate the impact of changes in media thickness on the magnetization process in particular at high temperatures numerically.

Methods: Nano-dot was modeled as a parallelepiped with uniaxial anisotropy which was regarded as a magnetically isolated system where no disturbance field of neighboring nano-dots. Simulation arrangements were implemented to evaluate the two viewpoints in the current heat-assisted magnetic recording, either coercivity, as well as writing field consume. Coercivity was gauged by inducing a magnetic field which linearly increased up to 2 Tesla for 2.5 ns at thermal equilibrium to the surrounding. In evaluating writing field consume, thermal field pulse which just below the Curie temperature was generated while the magnetic field inducing the nano-dot. These schemes investigations were based on the Landau-Lifshift- Gilbert equation which accommodates the fluctuation-dissipation theorem in calculating thermal fluctuation effect. Also, temperature dependent material parameters such as magnetic saturation, magnetic anisotropy, and exchange interaction, were taken into account.

Results: At room temperature, the coercive and nucleation fields are highly sensitive to the nano-dot thickness. Under thermal assistance, the writing field for 10 nm and 100 nm of the chosen thicknesses are 0.110 T and 0.125 T respectively. These writing grades are significantly lower than the coercivity of the media. For both thicknesses, zero field magnetization reversal phenomena are observed as indicated by the existences of the switching probabilities at H = 0.

Conclusion: This numerical study showed that using the heating assistance close to the Curie point, nanodots with the chosen thicknesses and magnetic parameters were probably to be magnetized even no driven magnetic field. Along with this result, magnetic field induction which required to utterly magnetizing was only in the sub-Tesla - about a tenth of the coercive field. During magnetization processes under thermal assistance, randomization of magnetic moments initiated the switching dynamic before the domain wall was nucleated and propagated to reach a single magnetized domain.

Keywords: Thermal characteristic, magnetization processes, magnetic, nanostructured materials, simulation, ferromagnetic nano-dot, perpendicular magnetic anisotropy.

[1]
Katayama, H.; Sawamura, S.; Ogimoto, Y.; Nakajima, J.; Kojima, K.; Ohta, K. New magnetic recording method using laser assisted read/write technologies. J. Magn. Soc. Jpn., 1999, 23, 233-236.
[2]
Schrelf, T.; Fidler, J.; Suess, D.; Scholz, W.; Tsiantos, V. Handbook of Advanced Magnetic Materials; vol. 1. Boston, MA Springer US, 2006.
[3]
Vemuri, S.H.; Kim, H.M.; Park, S.; Liu, Y.E.; Chung, P.S.; Jhon, M.S. Thermal management in heat-assisted magnetic recording. IEEE Trans. Magn., 2014, 50 11, 1-4.
[4]
Kryder, M.H.; Gage, E.C.; McDaniel, T.W.; Challener, W.A.; Rottmayer, R.E.; Ju, G.; Hsia, Y.T.; Erden, M.F. Heat assisted magnetic recording. Proc. IEEE, 2008, 96(11), 1810-1835.
[5]
Purnama, B.; Koga, M.; Nozaki, Y.; Matsuyama, K. Stochastic simulation of thermally assisted magnetization reversal in sub-100nm dots with perpendicular anisotropy. J. Magn. Magn. Mater., 2009, 321(9), 1325-1330.
[6]
Mansuripur, M.; Connell, G.A.N. Energetics of domain formation in thermomagnetic recording. J. Appl. Phys., 1984, 55(8), 3049-3055.
[7]
Lee, K.J.; Lee, T.D. Effect of thermal fluctuations on switching field of deep submicron sized soft magnetic thin film. J. Appl. Phys., 2002, 91(10), 7706.
[8]
Brown, W. Thermal fluctuation of fine ferromagnetic particles. IEEE Trans. Magn., 1979, 15(5), 1196-1208.
[9]
Boardman, R. Computer simulation studies of magnetic nanostructures. Computational Engineering and Design Group, School of Engineering Sciences, University of Southampton, United Kingdom, Ph.D. thesis, 2005.
[10]
Bahiraei, M.; Hosseinalipour, S.M.; Hangi, M. Numerical study and optimization of hydrothermal characteristics of Mn-Zn ferrite nanofluid within annulus in the presence of magnetic field. J. Supercond. Nov. Magn., 2014, 27(2), 527-534.
[11]
Stefanowicz, W.; Nistor, L.E.; Pizzini, S.; Kuch, W.; Buda-Prejbeanu, L.D.; Gaudin, G.; Auffret, S.; Rodmacq, B.; Vogel, J. Size dependence of magnetic switching in perpendicularly magnetized MgO/Co/Pt pillars close to the spin reorientation transition. Appl. Phys. Lett., 2014, 104(1)012404
[12]
Sun, J.Z. Resistance-area product and size dependence of spin-torque switching efficiency in CoFeB-MgO based magnetic tunnel junctions. Phys. Rev. B, 2017, 96(6)064437
[13]
Bi, M.; Wang, X.; Lu, H.; Zhang, L.; Deng, L.; Xie, J. Thickness dependence of magnetization reversal mechanism in perpendicularly magnetized L10 FePt films. J. Magn. Magn. Mater., 2017, 428, 412-416.
[14]
Tabasum, M.R.; Zighem, F.; Medina, J.D.L.T.; Encinas, A.; Piraux, L.; Nysten, B. Magnetic force microscopy investigation of arrays of nickel nanowires and nanotubes. Nanotechnology, 2014, 25(24)245707
[15]
Dumesnil, K.; Fernandez, S.; Avisou, A.; Dufour, C.; Rogalev, A.; Wilhelm, F.; Snoeck, E. Temperature and thickness dependence of the magnetization reversal in DyFe2/YFe2 exchange-coupled superlattices. Eur. Phys. J. B, 2009, 72(2), 159.
[16]
Herianto, N.A.; Rondonuwu, F.S.; Wibowo, N.A. Damping dependence of reversal magnetic field on co-based nano-ferromagnetic with thermal activation. Smart Sci., 2015, 3(1), 16-20.
[17]
Bahiraei, M.; Hangi, M. Flow and heat transfer characteristics of magnetic nanofluids: A review. J. Magn. Magn. Mater., 2015, 374, 125-138.
[18]
Lotfy, K.; Hassan, W.; Gabr, M.E. Thermomagnetic effect with two temperature theory for photothermal process under hydrostatic initial stress. Results Phys., 2017, 7, 3918-3927.
[19]
Bahiraei, M.; Hangi, M. Automatic cooling by means of thermomagnetic phenomenon of magnetic nanofluid in a toroidal loop. Appl. Therm. Eng., 2016, 107, 700-708.
[20]
Jager, T.; Léger, J.M.; Fratter, I.; Lier, P.; Pacholczyk, P. Magnetic cleanliness and thermomagnetic effect: Case study of the absolute scalar magnetometer and its environment on swarm satellites. In 2016 ESA Workshop on Aerospace EMC (Aerospace EMC), 2016, pp. 1-6.
[21]
Hertel, R. Viewpoint: For faster magnetic switching-destroy and rebuild. Physics, 2009, 2, 73.
[22]
Taniguchi, T. Spin torque switching in magnetic random access memory. Meet. Abstr., 2015, 16, 778-778.
[23]
Wibowo, N.A.; Rondonuwu, F.S.; Purnama, B. Low writing field on perpendicular nano-ferromagnetic. J. Magn., 2014, 19(3), 237-240.
[24]
Azizah, U.M.N.; Jessajas, M.B.; Handoyo, C.; Wibowo, N.A. Characteristic of nano-barium-ferrite as recording media using HAMR technology. Chiang Mai J. Sci., 2017, 44(4), 1669-1675.
[25]
Wibowo, N.A.; Trihandaru, S. Magnetic switching probability of perpendicularly magnetized nano-dot. J. Phys. Conf. Ser., 2016, 776(1)012027
[26]
Tagawa, I.; Ikeda, S.; Uehara, Y. High-performance write head design and materials. Fujitsu Sci. Tech. J., 2001, 37(2), 164-173.
[27]
Belhi, R.; Adjanoh, A.A.; Vogel, J.; Ayadi, M.; Abdelmoula, K. Magnetization reversal dynamics, nucleation, pinning, and domain wall propagation in perpendicularly magnetized ultrathin cobalt films: Influence of the Co deposition rate. J. Appl. Phys., 2010, 108(9)093924
[28]
Waseda, K.; Doi, R.; Purnama, B.; Yoshimura, S.; Nozaki, Y.; Matsuyama, K. Heat-assisted magnetization reversal using pulsed laser irradiation in patterned magnetic thin film with perpendicular anisotropy. IEEE Trans. Magn., 2008, 44(11), 2483-2486.
[29]
Suess, D.; Vogler, C.; Abert, C.; Bruckner, F.; Windl, R.; Breth, L. Fundamental limits in heat assisted magnetic recording and methods to overcome it with exchange spring structures. J. Appl. Phys., 2015, 117(16)163913


Rights & PermissionsPrintExport Cite as

Article Details

VOLUME: 9
ISSUE: 2
Year: 2019
Page: [259 - 266]
Pages: 8
DOI: 10.2174/2210681208666180507101809
Price: $58

Article Metrics

PDF: 15
HTML: 1