We report magnetic and transport properties of La 1Ϫx Ba x MnO 3 (xϭ0.05-0.33) epitaxial thin films. Compared with the corresponding bulk materials, the ferromagnetic transition temperature is reduced in the compressive strained La 1Ϫx Ba x MnO 3 thin films with xϭ0.3 and 0.33, but enhanced significantly in the tensile strained thin films with xр0.2. Especially, ferromagnetism and low field colossal magnetoresistance effect were observed around room temperature in xϭ0.1 thin film, and as xϭ0.05, a spin-canting insulating state in bulk shifts to ferromagnetic metallic state in thin film. The phase diagram of La 1Ϫx Ba x MnO 3 thin films was obtained, and strain effect on these novel properties was discussed.

Two-terminal multistate memory elements based on VO(2)/TiO(2) thin film microcantilevers are reported. Volatile and non-volatile multiple resistance states are programmed by current pulses at temperatures within the hysteretic region of the metal-insulator transition of VO(2). The memory mechanism is based on current-induced creation of metallic clusters by self-heating of micrometric suspended regions and resistive reading via percolation.

Room temperature structural, morphological, and enhanced ferroelectromagnetic properties of xBa0.7Ca0.3TiO3−(1−x)BaFe0.2Ti0.8O3 multiferroic composites Effect of electric field on magneto-transport properties in La2/3(Ca0.6Ba0.4)1/3MnO3/Pb(Zr0.52Ti0.48)O3 laminated composite

Spintronics, which takes advantage of both spin and charge degrees of freedom, is a promising key technique relevant to future applications of information and data storage. Ferromagnetic transition metal oxides, including perovskite manganites, represent the most promising materials for use as devices controlling magnetic states by an electric field at high temperature with high efficiency. This is because these materials possess a strong intrinsic relationship between charge and magnetism, showing ferromagnetism above room temperature by adjustment of carrier filling, in addition, particular magnetoelectric properties such as a colossal magnetoresistance phenomenon. Nevertheless, the device operation such a field control of magnetism has not been verified so far in manganites. It is essential to determine whether the magnetism of manganites can be controlled via carriers modulated by an electric field in these applications. Here the authors report on the direct demonstration of a simultaneous change in the magnetic and electric-transport properties in a ferromagnetic oxide field-effect transistor. A working temperature above 293K was achieved. This result should facilitate the use of spintronic devices in strongly correlated 3d-electron systems working at practical temperatures.

A programmable micromechanical resonator based on a VO2 thin film is reported. Multiple mechanical eigenfrequency states are programmed using Joule heating as local power source, gradually driving the phase transition of VO2 around its Metal-Insulator transition temperature. Phase coexistence of domains is used to tune the stiffness of the device via local control of internal stresses and mechanical properties. This study opens perspectives for developing mechanically configurable nanostructure arrays.

We report on conductive changes caused by electric bias-driven insulator-to-metal transition in VO2 thin films on a TiO2(001) substrate and observe the evolution of giant metallic domains to reveal their microscopic origin. The metallic domains are anisotropically formed along the direction of applied current or voltage. This anisotropic formation of metallic states causes abrupt increase of conductivity when the fraction rate of metallic states is low, conforming with the directed percolation model. Our results illustrate the importance of spatially localized phase transitions to tune conductive behavior.

We observed micro-scale phase separation in VO2 thin films on TiO2(001) substrates and investigated the relationship between the appearance of metallic domains and the abrupt resistive changes around the phase transition. The resistive changes are interpreted using a combined resistance model of the two phases, and the conductance evaluated from the visualized domain behavior was consistent with the electronic properties. These results indicate the importance of modifying conductive behavior spatially using a partial phase transition.

Plasmon resonances on 2D nanosquare arrays and their temperature‐dependent modulations are demonstrated using the insulator‐to‐metal transition (IMT) of VO2. A comparison between observed experimental trends and electromagnetic simulations reveals that the plasmon coupling is effective in the periodic 2D alignment of metallic VO2 nanosquares and results in a collective plasmon excitation. This plasmon excitation affects the optical responses of VO2 nanosquares in the mid‐infrared (IR) range through reduction of plasmon damping in relation to the specific band structure of VO2. This preliminary understanding is important for the elucidation of temperature‐dependent plasmon resonances. The IMT of VO2 produces temperature‐dependent plasmon resonances with respect to spectral features. The electrodynamic simulations reveal that these phenomena are based on plasmon coupling in the nanosquare array when each nanosquare acts as a single metallic domain. The hysteretic plasmon resonances are derived from resonant coupling between metallic VO2 nanosquares via the IMT nature of VO2, which results in temperature‐dependent changes in collective plasmon excitations in the nanosquare array.