We have fabricated K0.5Na0.5NbO3 (KNN) thin films on Pt substrates by a chemical solution deposition method and investigated the effect of K and Na excess (0–30 mol %) for KNN thin film. The KNN film with 20 mol % excess K and Na was an optimized KNN perovskite phase. From the Raman spectra, a change in the scattering mode was observed due to the chemical composition fluctuations of the excess K and Na. The peak of the (v 1 + v 5) internal vibrational mode in the NbO6 octahedra was split into two vibration modes which were shifted toward lower or higher wavenumbers depending on the K and Na cation deficiencies or redundancies.

A Josephson junction was fabricated by inducing a selective surface modification on a YBa2Cu3O7−y strip with an atomic force microscope (AFM). The surface modification in the field of conductive AFM tip results in the controlled growth of protrusions across the entire strip. By properly regulating the extent of AFM modification, we achieved a Josephson junction. The self-radiation power of about 50 pW at a resonant frequency of 22 GHz was detected from this junction, which is in excellent agreement with the Josephson frequency-voltage relationship.

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We have measured the electrical conductance of DNA-linked Au nanoparticle aggregates using the four probe method. FE-SEM images show that the Au nanoparticles are remained intact but not fused together. As the temperature increases under a constant relative humidity, the electrical conductance of Au nanoparticle aggregates linked by 12 base DNA molecules increases exponentially with an anomaly around the melting temperature of the linker DNAs due to the abrupt change of the amount of water molecules adsorbed on DNAs, but we could not observe such an anomaly for the aggregates linked by 24 base DNAs up to 71°C. We expect our results can be utilized as a DNA detection method which does not require any thermal-stringency wash before the measurement at each temperature.

We suggest an approach to the fabrication of versatile nanocomponents designed deliberately by selective Ga+ focused-ion-beam etching or Ar+ ion milling of single-crystalline Au nanoplates synthesized by the chemical reaction. The nanocomponents have various shapes like gear, wheel, dumbbell, square and letter “A” with in-plane size of about 400nm and thickness of 40–50nm. They can be picked up or moved freely one by one to be assembled into sophisticated nanodevices or micromachines. The applicability of our approach both to the fundamental research and to the applied research is discussed.

Frequency-locked and microwave-coupled arrays of high- superconducting Josephson junctions have been developed. The Josephson junctions were prepared on bicrystal MgO substrates using a pulsed laser ablation method. The maximum detected power of Josephson self-radiation, which is directly detected by a superheterodyne receiver with a central frequency of 22 GHz, from the arrays was enhanced with increasing number of Josephson junctions. The Josephson self-radiation properties of the arrays revealed a good quality of frequency locking and exactly satisfied the Josephson voltage-frequency relationship. A narrower linewidth of the Josephson self-radiation was obtained by increasing the number of Josephson junctions in the array.

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