title: Microwave-assisted switching of microscopic rings: correlation between nonlinear spin dynamics and critical microwave fields.
abstract: We have studied the spin dynamics of microscopic permalloy rings at GHz frequencies. Increasing the irradiation power, we observe first nonlinear spin dynamics and second microwave-assisted switching (MAS). We explore the MAS phase diagram as a function of microwave power and frequency f and, in particular, extract the critical microwave field hc(f). Its frequency dependence reflects characteristic eigenfrequencies from both the linear and nonlinear spin-wave spectrum. By comparing hc(f) with the different susceptibilities, we gain insight into the microscopic processes which might be the basis of a predictive theory of MAS.
authors.affiliation: Institut für Angewandte Physik und Mikrostrukturforschungszentrum, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany. jpodbiel@physnet.uni-hamburg.de
authors.forename: Jan
authors.initials: J
authors.lastname: Podbielski
authors.forename: Detlef
authors.initials: D
authors.lastname: Heitmann
authors.forename: Dirk
authors.initials: D
authors.lastname: Grundler