Spin-Polarized Carrier Injection in MOCVD-Grown YBCO/STO/LSMO Heterostructures with Underlying YBCO Layer

The oxide heterostructures composed of superconducting YBa2Cu3O7 bottom layer, the overlying ferromagnetic La 1−x Sr x MnO 3 film and SrTiO 3 as ultrathin (d ≈ 5 nm) barrier were grown heteroepitaxially onto LaAlO3 substrates by applying pulsed liquid injection metalorganic chemical vapour deposition technique. We report anomalous interface resistance increase with cooling just below superconductive transition temperature (T c ∼ = 85 K) and enhanced suppression of supercurrent of strip-like YBa 2 Cu 3 O 7 film due to spin-polarized carriers injected from the ferromagnetic manganite layer

Growth and Investigation of Oxide Heterostructures Based on Half-Metallic Fe3\text{}_{3}O4\text{}_{4}

We report thin films of ferromagnetic Fe$\text{}_{3}$O$\text{}_{4}$ (magnetite) grown by a reactive magnetron sputtering at T=300÷450°C on lattice-matched MgO, and bilayer structures composed of Fe$\text{}_{3}$O$\text{}_{4}$ and underlying epitaxial films of highly conductive electron-doped In$\text{}_{2}$O$\text{}_{3}$〈Sn〉, LaNiO$\text{}_{3}$, and antiferromagnetic CoO. The prepared Fe3O4/MgO films and the bilayer structures demonstrated clearly defined resistance anomaly at Verwey transition point (T$\text{}_{V}$≈100-120 K). Formation of high resistance interlayer was indicated between the adjacent conducting Fe3O4 and LaNiO3 layers. However, relatively low interface resistivity of about 0.1 Ω cm$\text{}^{2}$ (at T=300 K) was estimated for the patterned Fe3O4/In2O3〈Sn〉 bilayer structures. Vertical electrical transport measurements revealed strong nonlinearity in the I-U dependences of the Fe3O4/In2O3 〈Sn〉 interface at T<T$\text{}_{V}$

Spin-Polarized Carrier Injection in MOCVD-Grown YBCO/STO/LSMO Heterostructures with Underlying YBCO Layer

The oxide heterostructures composed of superconducting YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ bottom layer, the overlying ferromagnetic La$\text{}_{1-x}$Sr$\text{}_{x}$MnO$\text{}_{3}$ film and SrTiO$\text{}_{3}$ as ultrathin (d≈5 nm) barrier were grown heteroepitaxially onto LaAlO $\text{}_{3}$ substrates by applying pulsed liquid injection metalorganic chemical vapour deposition technique. We report anomalous interface resistance increase with cooling just below superconductive transition temperature (T$\text{}_{c}$≅85 K) and enhanced suppression of supercurrent of strip-like YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ film due to spin-polarized carriers injected from the ferromagnetic manganite layer

Spin-Polarized Carrier Injection in MOCVD-Grown YBCO/STO/LSMO Heterostructures with Underlying YBCO Layer

The oxide heterostructures composed of superconducting YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ bottom layer, the overlying ferromagnetic La$\text{}_{1-x}$Sr$\text{}_{x}$MnO$\text{}_{3}$ film and SrTiO$\text{}_{3}$ as ultrathin (d≈5 nm) barrier were grown heteroepitaxially onto LaAlO $\text{}_{3}$ substrates by applying pulsed liquid injection metalorganic chemical vapour deposition technique. We report anomalous interface resistance increase with cooling just below superconductive transition temperature (T$\text{}_{c}$≅85 K) and enhanced suppression of supercurrent of strip-like YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ film due to spin-polarized carriers injected from the ferromagnetic manganite layer

Magnetoresistive Properties of Manganite-Based Heterojunctions

Hole-doped $La_{2/3}Ba_{1/3}MnO_{3}$ (LBaMO), $La_{2/3}Ca_{1/3}MnO_{3}$ (LCaMO) and $La_{2/3}Ce_{1/3}MnO_{3}$ (LCeMO) thin films were grown heteroepitaxially on 0.1 wt.% Nb-doped $SrTiO_{3}(100)$ (STON) substrates by magnetron sputtering. The prepared LBaMO/STON, LCaMO/STON, LCeMO/STON heterostructures demonstrated nonlinear rectifying current-voltage characteristics. Negative magnetorestance values have been indicated at low bias, meanwhile bias-dependent magnetoresistance has been measured at positive bias voltage values U > U_d where U_d is the interfacial potential, corresponding to a steep current increase at a forward bias

Study of p-Fe₃O₄/n-(GaAs,Si) Heterostructures: Fabrication and Physical Properties

We report preparation and investigation of p -n heterostructures based on Fe₃O₄ thin films grown on semiconductor Si and GaAs substrates. Fe₃O₄ films with thickness ranging from 60 to 300 nm were grown at 350÷450°C using dc magnetron sputtering technique. The measurement of X-ray diffraction and reflection high energy electron diffraction revealed polycrystalline microstructure of thin Fe₃O₄ films deposited on both Si and GaAs substrate. Investigation of surface composition by X-ray photoelectron spectroscopy showed that Fe 2p peak consists of three main peaks, namely, metallic iron Fe(0), Fe(II), and Fe(III). Transport measurements of Fe₃O₄/n-(Si, GaAs) heterostructures demonstrated nonlinear current-voltage (I -V) dependences in the temperature range from 300 K to 78 K

Response of Grained La 0.67

It was found that the response of grained La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$ films to microwave radiation is of thermal nature. A nonresonant method for measuring of the electric resistance of grains was developed. It allows one to avoid the influence of the magnetic field of the wave on the measurement results. The measurements of the temperature dependences of the grain electric resistance indicate that in the vicinity of the maximum-resistance temperature T$\text{}_{m}$, the intrinsic electric resistance of the grains is more than by two orders of magnitude lower than the film resistance measured by applying the dc current. The obtained experimental results agree well with those given by resonant techniques