Preparation of the superconducting magnetostatic wave device by the heterostructure of the oxide superconductor/ferromagnet.

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On the electronic application of the superconductor, SQUID or SFQ circuit have utilized the feature of the flux quantumization, up-to-maximum. However, only the low surface resistance is noted for the field of superconducting microwave device. Thus, we have noted the application of the flux quantum to the microwave devices. In this idea, we have investigated and fabricated the prototype device of the superconducting magnetostatic wave device, in which the superconducting vortices and the magnetostatic wave propagating in the ferromagnetic matter. The effects of the interaction between the vortices and the magnetostatic wave are following two points. One is the magnetic energy of the magnetostatic wave will be absorbed by the vortices. The other is the switch of the superconductor to the normal state because of the vortices motion driven by the magnetostatic wave. In order to verify the consideration, we have performed two experiments, i.e., the measurement of the magnetostatic wave pro … More pagation for the situation of vortices in the superconductor, and the I-V measurement of the superconductor for the situation of the magnetostatic wave propagation.In those measurement, we have monitored the switching behavior of the superconducting state and normal state by the propagation of the magnetostatic wave. Furthermore, the magnetostatic wave is certainly absorbed when the superconductor is the normal state. This is the first step of the novel superconducting microwave device which is the switching device controlled by the interaction between vortices and the magnetostatic wave device.The superconducting magnetostatic wave device is suitable by the fabrication as the bilayered epitaxial thin films of the superconductor and the ferromagnet. In the present stage, Y-Fe garnet(YIG) ferrite is widely used as the magnetostatic wave propagator. However, the YIG cannot be grown on the perovskite type superconductor. Thus, our motivation is toward to the search of the new magnetic material for the waveguide of the magnetostatic wave which can construct the heteroepitaxial bilayer with the superconductor. The material we have noted is perovskite type manganite Pr_<0.85>Ca_<0.15>MnO_3 (PCMO).As the first step, we have prepared the PCMO thin film. The X-ray diffraction shows the high quality epitaxial thin films on the Nb-SrTiO_3(100). In the next, the electric properties are evaluated with the temperaturerange of 25 K〜300K. As the results, the LN_2 temperature of 77K, the PCMO has suitable Δ_r and low loss tangent. This means the PCMO is useful for the microwave application. Furthermore, the PCMO/YBCO heterostructure is formed as the band elimination filter of the superconducting magnetostatic wave device. In this experiment, microwave in the superconducting straight line can excited the magnetostatic wave in the PCMO thin films. Less