Colloquium: Dr. Chris Stock

Wed. Sep. 13 12:30 PM - Wed. Sep. 13 01:20 PM
Location: 1RC015

Dr. Chris Stock, University of Edinburgh

Center for Science at Extreme Conditions, School of Physics

Solitary magnetic excitations in CaFe2O4

Materials that display localized behavior have been studied extensively for the search of new properties including localized electronic and electromagnetic states. In the context of magnetism, single molecular magnets have been investigated owing to the ability to tune quantum properties as well as possible device applications, and mesoscopic magnetic structures have been created to confine magnetic excitations and manipulate frequencies. While localization in many of these systems is introduced through breaking up regular structures, spatial localization of energy has been known to exist in periodic structures that also contain strong nonlinear interactions. Examples of such include solitary waves (solitons) or also localized breather modes [1-2]. Here we demonstrate the presence of such localized modes in a classical S=5/2 periodic antiferromagnet where nonlinearity is introduced through magnetic anisotropy.  I will discuss a series of neutron scattering experiments on CaFe2O4 where two magnetic order parameters compete to confine excitations and also to allow the formation of new states near antiphase boundaries [3].


[1] A. J. Sievers and S. Takeno, Phys. Rev. Lett. 61, 970 (1988)

[2] S. Flach and C. R. Willis, Phys. Rep. 295, 181 (1998).

[3] C. Stock et al. Phys. Rev. Lett. 117, 017201 (2016).

Dr. Stock Seminar Poster [PDF]