Electro-forming of vacancy-doped metal-SrTiO3-metal structures

2011 ◽  
Vol 1337 ◽  
Author(s):  
Florian Hanzig ◽  
Juliane Seibt ◽  
Hartmut Stoecker ◽  
Barbara Abendroth ◽  
Dirk C. Meyer
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Physical Vapor Deposition ◽  
Oxygen Vacancies ◽  
Vacuum Annealing ◽  
Metal Insulator ◽  
Metal Structures ◽  
Wide Range ◽  
Metal Insulator Metal

ABSTRACTResistance switching in metal – insulator - metal (MIM) structures with transition metal oxides as the insulator material is a promising concept for upcoming non-volatile memories. The electronic properties of transition metal oxides can be tailored in a wide range by doping and external fields. In this study SrTiO3 single crystals are subjected to high temperature vacuum annealing. The vacuum annealing introduces oxygen vacancies, which act as donor centers. MIM stacks are produced by physical vapor deposition of Au and Ti contacts on the front and rear face of the SrTiO3 crystal. The time dependent forming of the MIM stacks under an external voltage is investigated for crystals with varying bulk conductivities. For continued formation, the resistivity increases up to failure of the system where no current can be measured anymore and switching becomes impossible.

scholarly journals Covalency, double-counting, and the metal-insulator phase diagram in transition metal oxides

2012 ◽  
Vol 86 (19) ◽  
Author(s):  
Xin Wang ◽  
M. J. Han ◽  
Luca de' Medici ◽  
Hyowon Park ◽  
C. A. Marianetti ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Double Counting ◽  
Metal Insulator

Controlled oxygen vacancy engineering on In2O3−x/CeO2−y nanotubes for highly selective and efficient electrocatalytic nitrogen reduction

2020 ◽  
Vol 7 (19) ◽  
pp. 3609-3619
Author(s):  
Zengyao Wang ◽  
Jianfeng Shen ◽  
Wenzhi Fu ◽  
Jiangwen Liao ◽  
Juncai Dong ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxygen Vacancy ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Oxygen Vacancies ◽  
Reduction Reaction ◽  
Nitrogen Reduction

Introducing and adjusting the oxygen vacancies (VO) of transition metal oxides has been proposed as a significant and effective way to tackle the sluggish nitrogen reduction reaction (NRR) in the electrocatalysis process.

scholarly journals Electret formation in transition metal oxides by electrochemical amorphization

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong-Jin Kim ◽  
Chan-Ho Yang
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Charge Density ◽  
Electric Fields ◽  
Transition Metal Oxides ◽  
Degrees Of Freedom ◽  
Permanent Magnets ◽  
Underlying Mechanism ◽  
Diffusion Reaction ◽  
Wide Range

AbstractTransition metal oxides (TMOs) are an important class of materials that show a wide range of functionalities involving spin, charge, and lattice degrees of freedom. The strong correlation between electrons in d-orbitals and the multivalence nature give rise to a variety of exotic electronic states ranging from insulator to superconductor and cause intriguing phase competition phenomena. Despite a burst of research on the multifarious functionalities in TMOs, little attention has been paid to the formation and integration of an electret—a type of quasi-permanent electric field generator useful for nanoscale functional devices as an electric counterpart to permanent magnets. Here, we find that an electret can be created in LaMnO3 thin films by tip-induced electric fields, with a considerable surface height change, via solid-state electrochemical amorphization. The surface charge density of the formed electret area reaches ~400 nC cm−2 and persists without significant charge reduction for more than a year. The temporal evolution of the surface height, charge density, and electric potential are systematically examined by scanning probe microscopy. The underlying mechanism is theoretically analyzed based on a drift-diffusion-reaction model, suggesting that positively charged particles, which are likely protons produced by the dissociation of water, play crucial roles as trapped charges and a catalysis to trigger amorphization. Our finding opens a new horizon for multifunctional TMOs.

Metal-insulator transition in 3d transition-metal oxides with ABO3 and A2BO4 type structures

1991 ◽  
Vol 185-189 ◽  
pp. 1295-1296 ◽  
Author(s):  
H. Eisaki ◽  
T. Ido ◽  
K. Magoshi ◽  
M. Mochizuki ◽  
H. Yamatsu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

scholarly journals Nanostructured transition metal oxides obtained by SPVD

2020 ◽  
Vol 7 ◽  
pp. 12
Author(s):  
Adriana Gabriela Plăiașu ◽  
Marian Cătălin Ducu ◽  
Sorin Georgian Moga ◽  
Aurelian Denis Negrea ◽  
Ecaterina Magdalena Modan
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Physical Vapor Deposition ◽  
Manganese Oxides ◽  
Oxidation States ◽  
Microstructural Characteristics ◽  
Original Process ◽  
Synthesis Parameters ◽  
D Orbitals

The interest in the unique properties associated with materials having structures on a nanometer scale has been increasing at an exponential rate in last decade. Transition metal oxides are preferred materials for catalytic applications due to their half-filled d orbitals that make them exist in different oxidation states. Transition metal oxides show a broad structural variety due to their ability to form phases of varying metal to oxygen ratios reflecting multiple stable oxidation states of the metal ions. The Solar Physical Vapor Deposition (SPVD) presented in the paper as elaboration method is an original process to prepare nanopowders working under concentrated sunlight in 2 kW solar furnaces. The influence of the synthesis parameters on the chemical and microstructural characteristics of zinc and manganese oxides synthesized nanophases has been systematically studied using XRD, SEM and EDX.

scholarly journals ORBITAL INSULATORS AND ORBITAL ORDER–DISORDER INDUCED METAL–INSULATOR TRANSITION IN TRANSITION-METAL OXIDES

2007 ◽  
Vol 21 (05) ◽  
pp. 691-706 ◽  
Author(s):  
DONG-MENG CHEN ◽  
LIANG-JIAN ZOU
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Thermal Fluctuation ◽  
Insulator Transition ◽  
Orbital Ordering ◽  
Excitation Spectra ◽  
Metal Insulator Transition ◽  
Orbital Order ◽  
Metal Insulator

The role of orbital ordering on metal–insulator transition in transition-metal oxides is investigated by the cluster self-consistent field approach in the strong correlation regime. A clear dependence of the insulating gap of single-particle excitation spectra on the orbital order parameter is found. The thermal fluctuation drives the orbital order–disorder transition, diminishes the gap and leads to the metal–insulator transition. The unusual temperature dependence of the orbital polarization in the orbital insulator is also manifested in the resonant X-ray scattering intensity.

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