Electrical noise study of spin glass dynamics in mesoscopic copper manganese

The electrical resistance of the archetypal spin glass $\underline{\rm Cu}$Mn is surprisingly sensitive to small changes in the spin configuration. This enhanced sensitivity results from long-range electron quantum interference at low temperatures. Due to this effect, substantial resistance noise is produced by spontaneous spin fluctuations below the spin-glass freezing transition. Described here are the results of noise experiments on extremely small 'mesoscopic' samples of $\underline{\rm Cu}$Mn. These samples are so small that only a handful of spin fluctuation events are observed during a measurement. Thus we have probed, for the first time, the glassy dynamics with sufficient microscopic detail to uncover the main features of the dynamical pattern. The results are incompatible with the simple 'droplet' picture of spin glasses which is currently in vogue. Noise statistics reveal instead very cooperative dynamics, closely resembling hierarchical dynamics models.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Israeloff, Nathan Eli

Contributors dc:contributor

• Weissman, Michael B.

• Physics, Condensed Matter

Statement dc:rights

• Copyright 1991 Israeloff, Nathan Eli

Language dc:language

eng

Identifier

AAI9124431
(UMI)AAI9124431

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/18999