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Quasi-one-dimensional electron gases (q1DEGs) have been obtained by fabricating LaAlO3 nanowires, using the technique of electrostatic spinning plus post annealing, above TiO2-terminated SrTiO3 substrate. The q1DEG exhibits an electronic transport behavior of variable range hopping with the one dimension characteristic. Visible light illumination produces a strong effect on transport process, depressing the resistance of the q1DEG by a factor up to 8. As expected, gating effect is weak at relative high temperatures, ~3.2% at 150K and 1.5% at 300K under a back gate of 200 V. Aided by light illumination, however, the gating effect is 35-fold amplified, and the resistance increases under not only negative gates but also positive gates, different from the normal gating effect without illumination. Possible explanations for these phenomena are given. [ABSTRACT FROM AUTHOR]

Basing on conductive atomic force microscopy, we presented a direct conductance mapping for the interface of the La0.67Sr0.33MnO3/Nb:SrTiO3 hetero-junction. The most remarkable observation is the presence of an interfacial layer in Nb:SrTiO3 adjacent to the manganite film. Within this layer, the AFM tip/Nb:SrTiO3 contact shows a current-voltage dependence that strongly deviates from Shockley equation, unlike a Schottky diode. Spatial extension of this layer is explored and possible transport mechanism in or outside this interfacial layer is discussed. The present work gives a direct intuitional image on the interface of manganite junction. The principle proven here can be extended to other complex oxide interfaces. [ABSTRACT FROM AUTHOR]

The transmittance of tungsten oxides can be adjusted by oxygen vacancy (Vo) concentration due to its electrochromic property. Here, we report an in-situ observation of resistive switching phenomenon in the oxygen-deficient WO3-x planar devices. Besides directly identifying the formation/rupture of dark-colored conductive filaments in oxide layer, the stripe-like WO3-x device demonstrated self-regulated switching behavior during the endurance testing, resulting in highly consistent switching parameters after a stabilizing process. For very high V os mobility was demonstrated in the WO3-x film by the pulse experiment, we suggested that the electric-field-induced homogeneous migration of V os was the physical origin for such unique switching characteristics. [ABSTRACT FROM AUTHOR]

The short circuit photocurrent (Isc) was found to be strongly dependent on the oxygen vacancies (VOs) distribution in Ag/Bi0.9La0.1FeO3/La0.7Sr0.3MnO3 heterostructures. In order to manipulate the VOs accumulated at either the Ag/Bi0.9La0.1FeO3 or the Bi0.9La0.1FeO3/La0.7Sr0.3MnO3 interface by pulse voltages, switchable or nonswitchable photocurrent can be observed without or with changing the polarization direction. The sign of photocurrent could be independent of the direction of polarization when the variation of diffusion current and the modulation of the Schottky barrier at the Ag/Bi0.9La0.1FeO3 interface induced by oxygen vacancies are large enough to offset those induced by polarization. Our work provides deep insights into the nature of photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities. [ABSTRACT FROM AUTHOR]

Bipolar resistive switching (RS) behavior was observed in epitaxially deposited TiO2-δ/La2/3Sr1/3MnO3 stacks. An intermediate initial state of this device demonstrated that the original resistive state would switch to either the higher or the lower state, depending only on the electrical polarity of the initial measurement. As the analogue intermediate states were obtained by device fabrication, the direct observation of these switching states was possible, knowing the microscopic physical origin of the RS effect. Based on x-ray photoelectron spectroscopy analysis, an understanding of this interesting phenomenon was proposed, well supporting the oxygen vacancy formation and recombination mechanism. [ABSTRACT FROM AUTHOR]

A resistive switching device based on the stacked α-Fe2O3/Nb-SrTiO3 is proposed and fabricated that demonstrates excellent bipolar resistive switching behaviors including the uniformity, endurance, and retention performance. The Schottky-like current-voltage characteristics correlated with set process were observed in both high resistive states (HRSs) and low resistive states (LRSs) of the device. Importantly, the anticrosstalk characteristic, possessing higher reversed-biased LRS resistance than the forwarded-biased HRS resistance, indicates the potential applications of the stacked α-Fe2O3/Nb-SrTiO3 for multilevel storage in the cross-bar memory arrays. The carrier injection and trapping mechanism is suggested to explain the observed phenomena. [ABSTRACT FROM AUTHOR]

We have fabricated micrometer-sized single-turn coils on top of charged CdSe/ZnSe quantum dot heterostructures by lithographical techniques. Current injection creates magnetic fields in the some 10 mT range, strong enough to modulate the hyperfine interaction. The very low coil inductance allows for generation of fast field transients. We demonstrate local control of the resident electron spin as well as read-out of the nuclear spin state on the 10 ns time scale by electrical current pulses. [ABSTRACT FROM AUTHOR]

Electronic structures of strained Nd1-xCaxMnO3 (NCMO) thin films with x=0 to 0.8 are investigated via x-ray absorption spectroscopy (XAS). The obtained O 1s spectra within the photon energy 529–535 eV can be decomposed into eg↑1, eg↑2, t2g↓, and eg↓ bands. Based on the assigned energy levels of these band states, the energies of magnetic exchange, crystal field and Jahn–Teller (JT) splitting are determined. Particularly, the JT splitting is around 0.8 eV, which is observed with O 1s XAS for the first time in NCMO thin films. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy measurements have been performed to elucidate local electronic and atomic structures of orthorhombic 3d-transition metal-doped yttrium manganites (YMnO3) with chemical formulae YMn2/3Me1/3O3 (Me=Co, Ni, and Cu). The Mn L3- and K-edges x-ray absorption near-edge structure (XANES) demonstrate the direct substitution of Me2+ for Mn3+, so that the positive effective charge of Mn ions are increased. Me-doping is also found to induce substantial broadening of the Mn L3-edge feature, which suggests enhancement of the delocalization of Mn 3d eg subbands and conductivity. Local spin density approximation (LSDA)+U (Hubbard U parameter) calculations were used to understand their electronic structures. [ABSTRACT FROM AUTHOR]