We report a near-field microwave microscopy based on a novel scanning probe—a long and narrow slot microfabricated on the convex surface of the dielectric resonator. The probe is mounted in the cylindrical waveguide. Tunable coupling to the probe is effectuated through the variable air gap. The whole probe is very compact, has a coaxial input, operates at 25–30 GHz, has a spatial resolution of 1–10 μm and, most important, has a low impedance of ∼20 Ω. This allows us to use it for characterization of metallic layers with high conductivity, in particular, thickness mapping.

We report a polarization-sensitive scanning microwave microscope based on a bimodal dielectric resonator with a cross-slit aperture. The microscope operates at ∼26 GHz in the reflection mode and has a subwavelength spatial resolution. It allows contactless mapping of the conductivity tensor, including magnetic-field-induced terms such as the Hall effect. We demonstrate local contactless measurement of the ordinary Hall effect in semiconducting wafers and of the extraordinary Hall effect in thin ferromagnetic Ni films. The latter yields out-of-plane magnetization. The microwave measurements are in good agreement with the dc Hall-effect measurements.

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Transthyretin (TTR) aggregation has been characterized to be responsible for several amyloid diseases. Fourier transform infrared (FTIR) spectroscopy, �uorescence, and atomic force microscopy (AFM) are used to investigate secondary structure changes in transthyretin, induced upon thermal denaturation and interaction with pentobarbital. Spectral analysis revealed a strong static quenching of the intrinsic �uorescence of TTR by pentobarbital with a binding constant (�) estimated at 2.092 × 10 3 M −1 . Fourier self-deconvolution (FSD) technique is used to evaluates intensity changes in the spectra of the component bands in the amide I and amide II regions due to the changes in pentobarbital concentration in the protein complex. e increases of the relative intensities of the peaks at 1614 cm −1 and 1507 cm −1 are due to the increase of pentobarbital concentrations which is linked to the formation of oligomers in the protein.

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Colossal magnetoresistive La 0.7 ( Pb 1−x Sr x ) 0.3 MnO 3 films for bolometer and magnetic sensor applicationsWe report phase-sensitive microwave studies of thin epitaxial manganite La 1−x Sr x MnO 3 films on SrTiO 3 substrate. The measurements were performed in the temperature range of 80-330 K using a contactless microwave scanning probe operating at 26 GHz with the aim of comparing dc resistivity and microwave resistivity. We find that the dc and the microwave resistivity of the La 0.8 Sr 0.2 MnO 3 are almost the same, while for the La 0.7 Sr 0.3 MnO 3 they are different above 200 K. Our analysis of different mechanisms of this discrepancy, together with our measurement of the ferromagnetic resonance on the same samples, yields the film inhomogeneity on the microscopic scale as the most probable explanation.

An inexpensive and easy experiment to measure the electrical resistance of high-T c superconductors as a function of temperature Am.We report a vacuum cryogenic ͑80 KϽTϽ350 K͒, near-field microwave scanning system based on a 90 GHz transmitting/receiving resonant slit antenna with a capacitive measurement of the probe-sample separation. The probe allows local measurement of resistance as a function of temperature with the spatial resolution of 20-50 m. The mm-wave probe is integrated with the eddy-current probe which allows global measurement of resistance of conducting and superconducting samples. This integrated probe is used for local study of the superconducting transition in high-T c superconducting thin films. The sensitivity of our present mm-wave probe is sufficient for probing conductivity in the normal state and in the superconducting state close to T c however not yet sufficient for probing conductivity variations far below superconducting transition temperature.

Beta amyloid (Aβ) aggregation has been characterized to be responsible for several amyloid diseases. Fourier transform infrared (FTIR) spectroscopy, fluorescence, and atomic force microscopy (AFM) are used to investigate induced changes in the secondary structure of Aβ upon thermal denaturation and interaction with propofol and L-arginine. Spectral analysis has revealed an effective static quenching for the intrinsic fluorescence of Aβ by propofol and l-arginine with binding constants of 2.81 × 10 2 M −1 for Aβ-propofol and 0.37 × 10 2 M −1 for Aβ-L-arginine. Fourier self-deconvolution (FSD) technique has been used to evaluate the relative intensity changes in the spectra of the component bands in the amide I and amide II regions at different ligand's concentration in the protein complex. The analysis showed a decrease in the intensities of the parallel beta bands of propofol and L-arginine interactions with Aβ, accompanied with an increase in the antiparallel bands for the Aβ-propofol interaction and a decrease for the Aβ-l-arginine interaction. The relative increase in peaks' intensities at 1694 cm −1 and 1531 cm −1 for the propofol interaction is linked to the formation of oligomers in the protein.