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HL: Halbleiterphysik

HL 55: Photonic crystals

HL 55.6: Talk

Friday, March 31, 2006, 12:45–13:00, BEY 154

Negative Refraction in Ferromagnet/Superconductor Superlattices — •A. Pimenov¹, P. P. Przyslupski², B. Dabrowski³, and A. Loidl¹ — ¹Experimentalphysik V, Center for Electronic Correlations and Magnetism, Universität Augsburg, 86135 Augsburg, Germany — ²Institute of Physics, Polish Academy of Sciences, 02-668 Warszawa, Poland — ³Department of Physics, Northern Illinois University, 60115 DeKalb, Illinois, USA

Negative refraction, which reverses many fundamental aspects of classical optics, can be obtained in systems with negative magnetic permeability and negative dielectric permittivity. During the last five years this negative refraction has been experimentally verified in a number of metamaterials and photonic crystals. In this work we demonstrate an experimental realization of negative refraction at terahertz frequencies and finite magnetic fields utilizing a multilayer stack of ferromagnetic and superconducting thin films [1]. In the present case the superconducting YBa₂Cu₃O₇ layers provide negative permittivity while negative permeability is achieved via ferromagnetic (La:Sr)MnO₃ layers for frequencies and magnetic fields close to the ferromagnetic resonance. In these superlattices the refractive index can be switched between positive and negative regions using external magnetic field as tuning parameter.

[1] A. Pimenov, P. P. Przyslupski, B. Dabrowski, and A. Loidl, Phys. Rev. Lett., in print