# Graduate Student / Postdoc Seminar

#### Dynamics of Ferromagnets: Averaging Methods, Bifurcation Diagrams, and Thermal Noise Effects

**Speaker:**
Katherine Newhall

**Location:**
Warren Weaver Hall 1302

**Date:**
Friday, March 28, 2014, 1 p.m.

**Synopsis:**

Driving nanomagnets by spin-polarized currents offers exciting prospects in magnetoelectronics, but the response of the magnet to such currents remains poorly understood. For a single domain ferromagnet, I will show that an averaged equation describing the diffusion of energy on a graph captures the low-damping dynamics of these systems. In particular, I compute the mean times of thermally assisted magnetization reversals in the finite temperature system, giving explicit expressions for the effective energy barriers conjectured to exist. I will then discuss the problem of extending the analysis to spatially non-uniform magnets, leading to a transition state theory for infinite dimensional Hamiltonian systems.