Date/time: 3:30 PM, Fri, Nov 5 2010.
Room: Sumwalt 102

Speaker: Yaroslaw Bazaliy

Title: Conventional magnetic switching with ballistic contribution.

Abstract:

A magnetic moment with an easy axis anisotropy energy and a time-dependent
external switching field applied along this axis is considered. Additional
small constant bias field is applied perpendicular to the axis. The moment
is switched by sweeping the axial field from a positive to a negative value.
It is found that the magnetic switching time is a non-monotonic function of
the field sweep time and exhibits a minimum. This unusual behavior is traced
back to the admixture of a ballistic rotation of the moment caused by the
perpendicular bias field in the presence of the variable switching field.
Analytic approximations are derived for the functional dependence of the
switching time on the field sweep rate and the value of the optimal field
sweep time. The existence of the optimal field sweep time has important
implications for the optimization of the magnetic memory devices.