CPM Seminar

The dynamics of the magnetization in small ferromagnetic structures is a topic of considerable current interest. The timing of this interest is largely attributable to rapid advances in magnetic recording technology, for which such dynamics will dictate the ultimate limits in speed and storage density. High speed magneto-optic imaging is now being used in an effort to gain new insight into micromagnetic dynamics.

The technique is directly analogous to electro-optic sampling of electronic systems. Applications to magnetics include studies of magnetization reversal[1], observations of spatially non-uniform modes of oscillation in ferromagnetic resonance[2], and characterizations of high speed magnetic recording devices[3]. The difficulties of understanding inherently nonlocal and nonlinear processes such as these provides fascinating challenges that must be addressed through a combination of experiment and numerical simulation. We are presently working on the comparison of experiment with the standard phenomenological model, and hope the experiments will ultimately lead us beyond this model.

1. A. Stankiewicz, W.K. Hiebert, G.E. Ballentine, K.W. Marsh, and M.R. Freeman, IEEE Trans. Mag. (July, 1998).
2. W.K. Hiebert, A. Stankiewicz, and M.R. Freeman, Phys. Rev. Lett 79, 1134 (1997).
3. Z. Shi, W.K. Hiebert, and M.R. Freeman, IEEE Trans. Mag. (in press).

Tuesday, November 24th 1998, 14:30
Ernest Rutherford Physics Building, Board room (room 104)