Schedule Jul 21, 2010
Disorder-tuned Approach to Critical Behavior in Thin-film Ferromagnets
Arthur Hebard, Univ. Florida

Using an apparatus in which thin films can be deposited and then immediately transferred without exposure to air into an adjoining cryostat, we present results on the disorder-induced changes in conductivity and magnetic behavior of thin-film ferromagnets. The experiments are motivated by the question of how disorder, which is known to localize spin-oriented carriers, affects magnetism in itinerant (band) ferromagnets. For Fe films we find a weak-localization quantum correction to the anomalous Hall effect, whereas in Gd films we observe an additional localizing, linear in temperature quantum correction to the conductivity due to scattering off spin waves. At higher stages of disorder, evidence will be presented for two distinct and rather surprising behaviors: for Gd films, a scale-dependent conductivity that collapses onto separate curves on each side of a metal-insulator transition, and for Fe and Co films, an anomalous Hall insulator behavior that can be ascribed to granularity.

Begin Flash full motion video, or Flash lower bandwidth video. (Or, right-click to download the 3gp file.)

Begin QuickTime full motion movie or Quicktime lower bandwidth movie.
(Or, right-click to download the lower bandwidth movie.) (Or, right-click to download the podcast.)

Begin streaming RealMedia. (Or, right-click to download the audio file.)

To begin viewing slides, click on the first slide below. (Or, view as pdf.)

[01] [02] [03] [04] [05] [06] [07] [08] [09] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47]

Author entry (protected)