We demonstrate the microwave detection effect in a granular La0.7Ca0.3MnO3 sample. Dc voltage generated by the sample in response to microwave irradiation below the Curie temperature is found to be dependent on the applied magnetic field. The magnetic field dependence of the dc voltage has a broad peak resembling an absorption line. The detection effect depends substantially on the magnetic history of the sample; however, identical measurement conditions provide reproducibility of the experimental results. The detected dc voltage increases linearly with microwave power and strongly depends on a bias current through the sample. According to the results of systematic measurements, there exist two contributions to a value of the detected output signal. The first is magneto-independent; it can be explained in the framework of a mechanism used traditionally for description of the rectification effect in metal–insulator–metal junctions with nonmagnetic metals. The other is magneto-dependent; it originates from the interplay between the spin-dependent current through magnetic tunnel junctions and spin dynamics of the grains, which form these junctions in the sample.

The transport and magnetotransport properties of a newly fabricated tunnel structure manganite/depletion layer/manganese silicide have been studied in the current-in-plane (CIP) geometry. A manganite depletion layer in the structure forms a potential barrier sandwiched between two conducting layers, one of manganite and the other of manganese silicide. The voltage-current characteristics of the

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