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Magnetoresistance of polycrystalline LCMO films in microwave magnetic field
|Andžej Lučun , Renata Butkutė , Andrius Maneikis , Oleg Kiprijanovič , Fiodoras Anisimovas , Jonas Gradauskas , Algirdas Sužiedėlis , Bonifacas Vengalis , Steponas Ašmontas|
Semiconductor Physics Institute, A.Gostauto 11, Vilnius LT-2600, Lithuania
Rare earth manganites demonstrate unusual electrical properties due to a strong interplay between spin, charge and orbital degrees of freedom. During the last years, major attention was paid to resistance change of both manganite films demonstrating various crystalline quality and related heterostructures by applying a permanent magnetic field (colossal magnetoresistance, tunneling magnetoresistance, grain boundary magnetoresistance etc). Recent investigation of polycrystalline manganite films in a microwave electrical field gave insightful information about their grain boundaries. However, up to now, microwave radiation-induced resistance change of the manganite films was studied taking into account a key role of high frequency electrical field on electrical properties of the manganites. Here we present new experimental evidence indicating importance of magnetic field component of microwave field (f = 9.4 GHz) on magnetoresistive properties of polycrystalline manganite films. Polycrystalline La0.7Ca0.3MnO3 films were grown on lucalox substrates by on-axis pulsed laser deposition. Microwave measurements revealed different character of the temperature-dependent electrical resistance of polycrystalline LCMO films placed in various positions of a waveguide. In the center of the waveguide, microwave electric field should determine resistance change under the influence of H10 wave. Near the narrow wall of the waveguide, where the electric component of the H10 wave decreases notably, the longitudinal microwave magnetic component should take part in the magnetoresistance of the polycrystalline LCMO film that was proved experimentally. Additional experiments with applied external permanent magnetic field confirmed the influence of microwave magnetic field on magnetoresistance of polycrystalline LCMO films.
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium K, by Andžej Lučun
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-15 12:35 Revised: 2009-06-07 00:44