Molecular Foundry Seminar

"Bit Patterned Media for High Density Magnetic Recording,"

Olav Hellwig, Hitachi Global Storage Technologies,

Tuesday, February 9th at 1:30 pm, Room 67-3111

Abstract:

Magnetron sputtered [Co/Pd] multilayer (ML) thin films are good model systems for bit patterned media (BPM) fabrication due to their easily controllable magnetic properties [1-3]. Deposition parameters, such as individual Co and Pd layer thicknesses, number of repeats, sputter pressure and temperature allow good control over magnetic properties, such as anisotropy, saturation magnetization, coercivity and magnetic microstructure [4,5]. One crucial issue for the successful implementation of BPM is the control of the switching field and the switching field distribution (SFD) in order to ensure exact addressability of individual pre-defined bits without overwriting adjacent down- or cross-track bits [2,6,7].

In my talk I will present a fabrication approach for BPM based on pre-patterned substrates and subsequent deposition of Co/Pd multilayers. I will develop different scenarios of how to possibly reach the addressability of single islands that is necessary for a successful introduction of BPM into hard disk drive technology. Such approaches include directed assembly of block copolymer for high quality pattern generation [8,9], advanced ECC media design for write field reduction and narrow SFD [2,10,11], control of dipolar dot-dot interactions [12], reduction of trench noise [13] and thermally assisted bit patterned recording (BPR) with high thermal gradients.

References:

[1] T. Thomson, G. Hu, and B. D. Terris, Phys. Rev. Lett. 96, 257204 (2006).

[2] O. Hellwig, T. Hauet, T. Thomson, E. Dobisz, J. D. Risner-Jamtgaard, D. Yaney, B. D. Terris and E. E. Fullerton, Appl. Phys. Lett. 95 (2009) 232505.

[3] J. M. Shaw, W. H. Rippard, S. E. Russek, T. Reith, and C. M. Falco, J. Appl. Phys. 101, 023909 (2007).

[4] M. S. Pierce, C. R. Buechler, L. B. Sorensen, J. J. Turner, S. D. Kevan, E. A. Jagla, J. M. Deutsch, T. Mai, K. Liu, J. Hunter Dunn, K. M. Chesnel, J. B. Kortright, O. Hellwig and E. E. Fullerton, Phys. Rev. Lett. 94, 017202 (2005).

[5] O. Hellwig, J. B. Kortright, A. Berger and E. E. Fullerton J. Magn. Magn. Mater. 319, 13 (2007).

[6] M.E. Schabes, J. Magn. Mag. Mat. 320, 2880 (2008).

[7] J. M. Shaw, S. E. Russek, T. Thomson, M. J. Donahue, B. D. Terris, O. Hellwig, E. Dobisz and M. L. Schneider, Phys. Rev. B 78, 024414 (2008).

[8] R. Ruiz, H. Kang, F. A. Detcheverry, E. Dobisz, D. S. Kercher, T. R. Albrecht, J. J. de Pablo, and P. F. Nealey, Science 321, 936 (2008).

[9] O. Hellwig, J. K. Bosworth, E. Dobisz, D. Kercher T. Hauet, G. Zeltzer, J. D. Risner-Jamtgaard, D. Yaney, and R. Ruiz, Appl. Phys. Lett., in print.

[10] T. Hauet, E. Dobisz, S. Florez, J. Park, B. Lengsfield, B.D. Terris and O. Hellwig

Appl. Phys. Lett. 95 (2009) 262504.

[11] M. Grobis, E. Dobisz, O. Hellwig, M. Schabes, T. Hauet, G. Zeltzer, and T. Albrecht,

Appl. Phys. Lett. 96 (2010) 052509.

[12] O. Hellwig, A. Berger, T. Thomson, E. Dobisz , H. Yang, Z. Bandic, D. Kercher and E. E. Fullerton, Appl. Phys. Lett. 90, 162516 (2007).

[13] O. Hellwig, A. Moser, E. Dobisz, Z. Bandic, H. Yang, D. S. Kercher, J. D. Risner-Jamtgaard, D. Yaney and E. E. Fullerton, Appl. Phys. Lett. 93 (2008) 192501.