ACTA

Magnetoresistance of Polycrystalline La_0.7Ca_0.3MnO₃ Films in a Microwave Magnetic Field

A. Lučun^a, R. Butkutė^a, A. Maneikis^a, O. Kiprijanovič^a, F. Anisimovas^a, J. Gradauskas^{a, b}A. Sužiedėlis^{a, b}B. Vengalis^{a, b}Ž. Kancleris^a and S. Ašmontas^{a, c}
^aSemiconductor Physics Institute, A. Goštauto 11, 01108 Vilnius, Lithuania
^bVilnius Gediminas Technical University, Saulėtekio al. 11, 2040 Vilnius, Lithuania
^cKTU Panevėžys Institute, Klaipėdos 3, 5319 Panevėžys, Lithuania

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Received: 04 09 2006;

We present new experimental evidence indicating the importance of magnetic field component of microwave field (f=9.4 GHz) for magnetoresistive properties of polycrystalline La_0.7Ca_0.3MnO₃ films. The microwave measurements revealed a different character of the temperature-dependent electrical resistance of polycrystalline La_0.7Ca_0.3MnO₃ films placed in the centre (maximal amplitude of H₁₀ wave vector) and at a narrow wall of the wave-guide (reduced H₁₀ amplitude). Theoretical estimations of the influence of substrate onto distribution of microwave electric and magnetic fields in the waveguide were performed using the finite-difference time-domain method.

DOI: 10.12693/APhysPolA.111.147
PACS numbers: 75.47.Gk, 75.47.Lx, 07.57.Kp