Jahn-Teller Effects in Transition Metal Oxides

2001 ◽  
pp. 141-151
Author(s):  
Despina Louca
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Jahn Teller

Effect of Jahn-Teller distortions on the structural and magnetic ordering in perovskite-type transition-metal oxides

2008 ◽  
Vol 72 (8) ◽  
pp. 1159-1161 ◽  
Author(s):  
Kh. G. Bogdanova ◽  
A. R. Bulatov ◽  
V. A. Golenishchev-Kutuzov ◽  
R. I. Kalimullin ◽  
A. A. Potapov
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Magnetic Ordering ◽  
Type Transition ◽  
Jahn Teller ◽  
Perovskite Type

BOND-LENGTH FLUCTUATIONS IN TRANSITION-METAL OXIDES

2005 ◽  
Vol 19 (22) ◽  
pp. 1057-1081 ◽  
Author(s):  
J. B. GOODENOUGH ◽  
F. RIVADULLA
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Bond Length ◽  
Transition Metal Oxides ◽  
Atomic Diffusion ◽  
First Order ◽  
Higher Spin ◽  
Jahn Teller ◽  
Long Range Ordering ◽  
Double Well Potential

The several origins of bond-length fluctuations found in transition-metal oxides are illustrated by specific examples. Special emphasis is given to the first-order character of the transition from localized to itinerant electronic behavior, which occurs where the operative bonding has a double-well potential energy. This first-order transition is a general phenomenon applying to single-valent and mixed-valent systems with either cation-cation or cation-anion-cation operative bonding. A transition from bond-length fluctuations to long-range ordering of the bond character is found below a Tt where Tt is too low for phase separation by atomic diffusion. Where Jahn–Teller site distortions or low-spin to higher-spin site excitations are also present, competitive bond ordering can give complex phase diagrams.

Electronic Structures in LaTiO3/LaAlO3 Multilayers

2013 ◽  
Vol 771 ◽  
pp. 7-11 ◽  
Author(s):  
Er Jun Kan
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Density Functional ◽  
Orbital Ordering ◽  
Crystal Field Theory ◽  
Teller Distortion ◽  
Jahn Teller ◽  
Important Direction ◽  
Jahn Teller Distortion

We demonstrate the existence of a hidden degree of freedom controlling the orbitalordering in [LaTiO1/[LaAlO5 multilayers with comprehensive density-functional theorycalculations. The orbitals of two-dimensional (2D) 3d1state of Ti atoms in the multilayers alwayscontain large dxy components, which is unexpected from crystal field theory (first Jahn-Tellerdistortion). The competition between first and second Jahn-Teller distortion induces variousmagnetic properties. Thus, transition-metal oxides/non-transition-metal oxides multilayers mayprovide an important direction to manipulate the spin and orbital ordering in magnetic materials.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

1992 ◽  
Vol 50 (2) ◽  
pp. 1624-1625
Author(s):  
Michel Fialin ◽  
Guy Rémond
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Electrostatic Charge ◽  
Carbon Layer ◽  
Sample Holder ◽  
Rock Matrix ◽  
Electrical Discharges ◽  
Thin Carbon ◽  
Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

scholarly journals Electronic Phenomena of Transition Metal Oxides

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 256
Author(s):  
Christian Rodenbücher ◽  
Kristof Szot
Keyword(s):  
Solid State ◽  
Transition Metal ◽  
Metal Oxides ◽  
Real World ◽  
Transition Metal Oxides ◽  
Major Research ◽  
Research Fields ◽  
Real World Applications

Transition metal oxides with ABO3 or BO2 structures have become one of the major research fields in solid state science, as they exhibit an impressive variety of unusual and exotic phenomena with potential for their exploitation in real-world applications [...]

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