Submicron Size Particles of Magnetic Films and Multilayers
The area between the micro- and macroscopic ranges of magnetism offers an exciting field for research and development. The design of magnets for small-scale applications requires several physical parameters to be simultaneously controlled and matched to each other. First one should control the exchange energy, the crystalline anisotropy and the atomic magnetic moment; material parameters governing e. g. the ordering temperature and magnetization of the material. This may be accomplished by applying modern preparation techniques to make thin films and layered materials, yielding a variety of intrinsic magnetic properties . Second, the demagnetizing effects that are inevitably introduced when the lateral extensions of the material are limited must be incorporated in the design to yield the proper zero-field state as well as dynamic response . There are many questions to answer about the zero-field state of a magnetic particle, for instance how the critical sizes for formation of a single domain (SD) can be reached. SD particles with two possible orientations of their moment in zero field — a binary bit — are suggested as building blocks of a novel magnetic memory . At the same time as a stable zero-field state is obtained, magnetization reversal should occur at an appropriate field with a narrow distribution of switching fields among the particles.
KeywordsVortex Ethyl Anisotropy Acetone Lactate
Unable to display preview. Download preview PDF.
- 1.Bland, J. A. C. and Heinrich, B. (1994) Ultrathm Magnetic Structures I and II. Springer, Berlin.Google Scholar
- 2.See e. g. Aharoni, A. (1996) Introduction to the Theory of Ferromagnelism. Clarendon Press, Oxford.Google Scholar
- 3.See e. g. White, R. L., New, R. M. H. and Pease, R. F. W. (1997) Patterned media: A viable Route to 50 Gbit/in2 and Up for Magnetic Recording?, IEEE Trans. Magn. 33, 990–995. Chou, S. Y. (1997) Patterned Magnetic Nanostructures and Quantized Magnetic Disks, Proc. IEEE 85, 652-671.CrossRefGoogle Scholar
- Plumer, M., van Ek, J. and Weiler, D. (eds.) (2001) The Physics of Ultrahigh-Density Magnetic Recording. Springer, Berlin.Google Scholar
- 5.Hanson, M., Kazakova, O., Blomqvist, P., Wäppling, R. and Nilsson, B. (2002) Magnetic domain structures in submicron size particles of epitaxial Fe (001): shape anisotropy and thickness dependence, (Unpublished).Google Scholar
- 10.Kazakova, O., Hanson, M., Blomqvist, P. and Wäppling, R. (2002) Interplay between shape and magnetocrystalline anisotropies in patterned bcc Fe/Co multilayers, (Unpublished).Google Scholar
- 11.Kazakova, O., Hanson, M., Blixt, A. M. and Hjörvarsson (2002) Domain structure of circular and ring magnets, J. Magn. Magn. Material, (In press).Google Scholar
- 15.Svedberg, E. B., Sandström, P., Sundgren, J. E., Greene, J. E. and Madsen, L. D. (1999) Epitaxial growth of Ni on MgO(002) 1x1: surface interaction vs. multidomain strain relief, Surface Science 429 206–216.Google Scholar
- 17.Morrish, A. H. (1965) The Physical Principles of Magnetism. Wiley, New York.Google Scholar
- 18.Zhu, J., Zheng, Y., Prinz, G. (2000) Ultrahigh density vertical magnetoresistive random access memory J. Appl. Phys. 87 6668–6673.Google Scholar
- 20.See e. g. Rothman, J., Kläui, M., Lopez-Diaz, L., Vaz, C. A. F., Bleloch, A., Bland, J. A. C., Cui Z. and Speaks, R. (2001) Observation of a Bi-Domain State and Nucleation Free Switching in Mesoscopic Ring Magnets. Phys. Rev. Lett. 86, 1098–1101. Kläui, M., Lopez-Diaz, L., Rothman, J., Vaz, C. A. F., Bland, J. A. C. and Cui, Z. (2002) Switching properties of free-standing epitaxial ring magnets, J. Magn. Magn. Mater. 240, 7-10.CrossRefGoogle Scholar