Rapid advances in information technology rely on high-speed and large-capacity nonvolatile memories. A number of alternatives to contemporary Flash memory have been extensively studied obtain a more powerful functional memory. We review the current status one alternatives, resistance random access (ReRAM), which uses resistive switching phenomenon found transition metal oxides. ReRAM cell is capacitor-like structure composed insulating or semiconducting oxides that exhibits reversible...

We have characterized the vertical transport properties of epitaxial layered structures composed Pr0.7Ca0.3MnO3(PCMO) sandwiched between SrRuO3(SRO) bottom electrode and several kinds top electrodes such as SRO, Pt, Au, Ag, Ti. Among structures, Ti∕PCMO∕SRO is distinct due to a rectifying I–V characteristic with large hysteresis. Corresponding hysteresis characteristics, contact resistance Ti∕PCMO interface reversibly switches two stable states by applying pulsed voltage stress. propose...

Transport properties have been studied for a perovskite heterojunction consisting of SrRuO$_{3}$ (SRO) film epitaxially grown on SrTi$_{0.99}$Nb$_{0.01}$O$_{3}$ (Nb:STO) substrate. The SRO/Nb:STO interface exhibits rectifying current-voltage ($I$-$V$) characteristics agreeing with those Schottky junction composed deep work-function metal and an $n$-type semiconductor (Nb:STO). A hysteresis appears in the $I$-$V$ characteristics, where high resistance low states are induced by reverse forward...

We investigated the electrical properties of heteroepitaxial oxide Schottky junctions, $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_{3}∕\mathrm{Sr}{\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{x}{\mathrm{O}}_{3}$ $(0.0002\ensuremath{\leqslant}x\ensuremath{\leqslant}0.02)$. The overall features agree with those a conventional semiconductor junction, as exemplified by rectifying current $(I)$-voltage $(V)$ characteristics linear $\mathrm{log}\phantom{\rule{0.2em}{0ex}}I\text{\ensuremath{-}}V$...

Abstract This work reports a resistive switching effect observed at rectifying Pt/Bi 1–δ FeO 3 interfaces and the impact of Bi deficiencies on its characteristics. Since provide hole carriers in BiFeO , Bi‐deficient films act as p‐type semiconductor. As deficiency increased, leakage current tended to increase, finally, hysteretic current–voltage ( I – V ) characteristics were observed. In measured voltage‐sweep frequency 1 kHz, positive negative peaks originating from ferroelectric...

We have studied the transport and resistance switching properties of Ti∕Sm0.7Ca0.3MnO3 (n unit cells)/La0.7Sr0.3MnO3 [Ti∕SCMO(n)∕LSMO] layered structures. The metal-to-metal contact Ti/LSMO junction (n=0) does not exhibit effect, while insertion a very thin insulating SCMO layer (n⩾1) induces effect. As thickness (n) increases, amplitude grows response gets faster. This indicates that as several u.c. adjacent to interface works an active source for

The electrical properties of ferroelectric Hf–Zr–O ultrathin films, particularly the dependences remnant polarization, leakage current, coercive field, and breakdown field on metal composition film thickness, are systematically examined. Physical analyses show that films in this experiment consist polycrystalline grains contain both dielectric phases. It is found changes thickness strongly influence polarization current simultaneously. In contrast, was relatively unaffected by these...

We have measured the flux flow Hall effect in superconducting state of various high- ${T}_{c}$ superconductors (HTSC) from underdoped to overdoped regime. show that sign is universal and determined by doping level; electronlike regime holelike This tendency contradicts prediction time dependent Ginzburg-Landau equation based on s-wave weak coupling theory, suggesting such a theory fails evaluate force acting vortices HTSC. discrepancy may be attributed novel electronic structure vortex

We investigated the Ca-composition dependence of resistive switching (RS) characteristics and band diagrams in $\text{Ti}/{\text{Pr}}_{1\ensuremath{-}x}{\text{Ca}}_{x}{\text{MnO}}_{3}$ $[\text{PCMO}(x)]$ junctions impact oxygen vacancies on diagrams. Hysteretic current-voltage characteristics, i.e., RS effect, were observed for $\text{Ti}/\text{PCMO}(x)$ with $x<0.8$, whereas consisting $n$-type semiconducting $\text{PCMO}(x)$ $x>0.8$ showed almost no effect. The ratio...

Photoinduced transitions from a Mott insulator to metal have been investigated in the undoped cuprates Nd${}_{2}$CuO${}_{4}$ and La${}_{2}$CuO${}_{4}$ by applying femtosecond pump-probe absorption spectroscopy epitaxially grown thin-film samples. In Nd${}_{2}$CuO${}_{4}$, metallic state is generated with low excitation photon density less than 0.01 photons/Cu decays within 40 fs via rapid photocarrier recombination. Residual photocarriers are localized effect of charge-spin coupling,...

We demonstrate electrostatic control of the metal-insulator transition in typical correlated-electron material NdNiO3 through a large effective capacitance electric double layer at electrolyte/NdNiO3 interface. The temperature (TMI) is shown to decrease drastically with increasing hole concentration application negative gate voltage (VG). shift TMI (|ΔTMI|) larger for thinner NdNiO3; VG −2.5 V, |ΔTMI| 5-nm-thick as 40 K, and resistivity change near 95 K one order magnitude. This study may be...

Charge and lattice dynamics caused by photocarrier doping of the undoped cuprates ${\text{Nd}}_{2}{\text{CuO}}_{4}$ ${\text{La}}_{2}{\text{CuO}}_{4}$ were studied femtosecond absorption spectroscopy. In both compounds, a metallic state is formed just after photoexcitation decays within $\ensuremath{\sim}200\text{ }\text{fs}$. Photogenerated electrons holes are subsequently localized due to charge-spin coupling, producing midgap absorptions at different energies. Charge-phonon coupling also...

Protonation into VO2 by means of the electrolyte-gating technique and its use in reversible control electronic states are demonstrated. causes both a lattice deformation electron doping VO2; these suppress metal–insulator transition stabilize metallic phase. The finding provides clues to understanding mechanism electrolyte gating metal oxides. As service our authors readers, this journal supporting information supplied authors. Such materials peer reviewed may be re-organized for online...

We investigated the effects of Cr and Nb doping on metal–insulator transition (MIT) single-oriented VO2 films deposited Al2O3 substrates. The MIT temperature (TMI) increased with trivalent doping, whereas it decreased pentavalent doping. coefficient resistance (TCR) thermal hysteresis width (ΔTMI) were suppressed by was about twice as effective for decreasing TCR ΔTMI. found that maximum ΔTMI doped have a correlation lattice constant irrespective elements, suggesting deformation caused...

Hf0.5Zr0.5O2 thin films are not always ferroelectric. This work investigates the impact of annealing temperature and time on crystalline structures dielectric properties 10 nm thick films. It is found that tetragonal phase crystal formed from amorphous film firstly, then transforms to orthorhombic monoclinic phases, in accordance with time. The volume fraction film, which known as origin ferroelectricity, becomes dominant a certain range condition. Thus, responsible for anti-ferroelectric,...

All epitaxial oxide magnetic tunnel junctions, ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}/{\mathrm{SrTiO}}_{3}/{\mathrm{SrRuO}}_{3}$ trilayer films, composed of ferromagnetic and metallic electrodes were fabricated on STO(001) substrates. Inverse magnetoresistance (TMR), i.e., higher lower junction resistance levels in parallel anti-parallel magnetization configurations, respectively, was observed, indicating the negative spin polarization ${\mathrm{SrRuO}}_{3}$ contrast to...

We have fabricated epitaxial Pr0.7Ca0.3MnO3∕SrTi0.9998Nb0.0002O3 (PCMO∕Nb:STO) junctions and characterized the interface electronic properties. The PCMO∕Nb:STO show highly rectifying current density–voltage (J–V) characteristics without an apparent breakdown in reverse bias up to 100V at room temperature. J–V of diodes agree well with conventional diffusion theory for a p-n diode. forward capacitance-voltage result identical built-in potential ∼0.7eV. Based on experimental results, plausible...

A prototype Mott transistor, the electric double layer transistor with a strained CaMnO3 thin film, is fabricated. As predicted by strain phase diagram of electron-doped manganite films, device compressively exhibits an immense conductivity modulation upon applying tiny gate voltage 2 V. Detailed facts importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted authors. Please note:...

Ferroelectric resistive switching was artificially induced in a conductive ferroelectric capacitor by inserting thin dielectric layer at an electrode/ferroelectric interface. capacitors consisting of semiconducting Bi-deficient Bi1−δFeO3 layers with SrRuO3 electrodes showed no switching, but emerged these when LaFeO3 inserted one the SrRuO3/Bi1−δFeO3 interfaces. In addition to SrRuO3/LaFeO3/Bi1−δFeO3/SrRuO3 devices rectifying current–voltage characteristics, suggesting asymmetric potential...

Effects of epitaxial strain on metal–insulator transitions (MITs) VO2 films grown MgF2 (001) substrates were examined. A partially tensile-strained film deposited at 420 °C showed an MIT temperature (TMI) 318 K whereas that a relaxed 520 was about 331 K. Raman scattering measurements the affects V–V vibration modes in insulating phase. The TMI strained is lower as result shorter distance and reduced twisting angle dimer caused by in-plane tensile strain.

Tunnel electroresistance in ferroelectric tunnel junctions (FTJs) has attracted considerable interest, because of a promising application to nonvolatile memories. Development thin‐film devices requires atomic‐scale band‐structure engineering based on depolarization‐field effects at interfaces. By using FTJs consisting ultrathin layers the prototypical BaTiO 3 , it is demonstrated that surface termination contact with simple‐metal electrode critically affects properties electroresistance....

We have fabricated compact optical modulators consisting of a Si waveguide with VO2 cladding layer. These devices showed sharp decrease in transmittance at around 60 °C, which is attributable to the metal-insulator transition By systematically varying length device, we evaluated transmission losses per unit device be 1.27 dB/µm, when layer was insulating (ON) state and 4.55 dB/µm it metallic (OFF) state. Furthermore, found that an additional loss OFF state, structural effect. As result,...

Doped indium oxides, such as tin oxide (ITO), have been used transparent conducting materials and recently attracted increasing interest thin-film channel for high-performance field-effect transistors. In numerous studies on crystalline ITO, stable bixbyite-type (cubic) metastable corundum-type (rhombohedral) phases investigated. Here, we demonstrate an epitaxial stabilization of the ITO polytype having Rh2O3-II-type (space group: Pbna) orthorhombic structure using perovskite (110) DyScO3...

Heterointerfaces of correlated electron oxides provide a good laboratory to explore novel electronic states induced by the coupling among spin, charge, and orbital degrees freedom. For detail understanding complex interface states, it is indispensable elucidate band profiles materials. Here we report $\text{Mott-insulator}/\text{Nb}:{\text{SrTiO}}_{3}$ heterojunctions revealed optical-spectroscopic transport measurements. Photocurrent action spectra indicate existence bending discontinuity...