Stochastic Dynamics in Magnetic Systems

Stochastic Dynamics in Magnetic Systems

Katie Newhall
UNC Chapel Hill
11:00 am in Manchester 020
Thursday, October 18, 2018

 

As magnetic devices become smaller, understanding thermal noise effects becomes more important to ensuring proper function.  One example is thermally-induced transition times in the case of spin-polarized currents for which standard reaction rate theory of Kramers is no longer valid.  I provide a theoretical basis for the experimentally observed Neel-Brown-type formula with effective energy barrier, by capturing the low-damping dynamics of this system. When considering spatially extended systems, I show equivalence between the microcanonical and canonical distributions in infinite dimensions, thus the mechanism for metastability is no longer an energy.  I will also present interesting scalings for deriving the Landau Lifshitz equation for magnetic systems from stochastic Metropolis Hastings dynamics.  This forms a basis for understanding how spatially colored noise affects dynamics in spatially extended magnetic systems of spin-vectors.

Reception – 10:30am, Manc-336
Host: John Gemmer, gemmerj@wfu.edu

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