scholarly journals Chiral molecular conductor with an insulator–metal transition close to room temperature

2020 ◽  
Vol 56 (66) ◽  
pp. 9497-9500 ◽  
Author(s):  
Jonathan I. Short ◽  
Toby J. Blundell ◽  
Sara J. Krivickas ◽  
Songjie Yang ◽  
John D. Wallis ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molecular Conductor ◽  
Insulator Metal Transition

Synthesis of a chiral molecular metal which remains metallic down to at least 4.2 K and exhibits room-temperature switching capabilities.

Evolution of crystal structure of dual layered molecular conductor (ET)4ZnBr4(C6H4Cl2) with temperature

CrystEngComm ◽  
2021 ◽  
Author(s):  
Gennady V. Shilov ◽  
Elena I. Zhilyaeva ◽  
Sergey M. Aldoshin ◽  
Alexandra M Flakina ◽  
Rustem B. Lyubovskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Single Crystal ◽  
Room Temperature ◽  
Organic Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Molecular Conductor ◽  
Abrupt Changes

Electrical resistivity measurements of a dual layered organic conductor (ET)4ZnBr4(1,2-C6H4Cl2) above room temperature show abrupt changes in resistivity at 320 K. Single-crystal X-ray diffraction studies in the 100-350 K range...

scholarly journals Ultrafast manipulation of mirror domain walls in a charge density wave

2018 ◽  
Vol 4 (10) ◽  
pp. eaau5501 ◽  
Author(s):  
Alfred Zong ◽  
Xiaozhe Shen ◽  
Anshul Kogar ◽  
Linda Ye ◽  
Carolyn Marks ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Domain Walls ◽  
Density Wave ◽  
Charge Ordering ◽  
Time Resolved ◽  
Insulator Metal Transition ◽  
Femtosecond Light Pulse ◽  
A Charge

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS2. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.

Thermal Diffusivity and Conductivity of La0.7Ca0.3-xSrxMnO3 (x=0 to 0.10)

2012 ◽  
Vol 501 ◽  
pp. 319-323
Author(s):  
Hasan A. Alwi ◽  
Lay S. Ewe ◽  
Zahari Ibrahim ◽  
Noor B. Ibrahim ◽  
Roslan Abd-Shukor
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Transition Temperature ◽  
Thermal Diffusivity ◽  
Electrical Properties ◽  
Room Temperature ◽  
Electronic Contribution ◽  
Insulator Metal Transition ◽  
Thermal And Electrical Properties

We report the room temperature thermal conductivity κ and thermal diffusivity α of polycrystalline La0.7Ca0.3-xSrxMnO3 for x = 0 to 0.1. The samples were prepared by heating at 1220 and 1320oC. The insulator-metal transition temperature, TIM and thermal diffusivity increased with Sr content. Phonon was the dominant contributor to thermal conductivity and the electronic contribution was less than 1%. Enhancement of electrical conductivity σ and thermal diffusivity for x ≥ 0.08 was observed in both series of samples. The grain size of the samples (28 to 46 µm) does not show any affect on the thermal and electrical properties.

Room-Temperature First-Order Phase Transition in a Charge-Disproportionated Molecular Conductor (MeEDO-TTF)2PF6

2008 ◽  
Vol 20 (24) ◽  
pp. 7551-7562 ◽  
Author(s):  
Xiangfeng Shao ◽  
Yoshiaki Nakano ◽  
Masafumi Sakata ◽  
Hideki Yamochi ◽  
Yukihiro Yoshida ◽  
...  
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
Room Temperature ◽  
First Order ◽  
Molecular Conductor ◽  
First Order Phase Transition ◽  
A Charge ◽  
First Order Phase

Research on Thermal Properties of Insulator-Metal Transition at Room Temperature in Sm1-xCaxMnO3

2019 ◽  
Author(s):  
Ruxia Chang ◽  
Desong Fan ◽  
Qiang Li
Keyword(s):  
Room Temperature ◽  
Bulk Material ◽  
Laser Flash ◽  
Solid State Reaction Method ◽  
Flash Method ◽  
X Ray Diffraction ◽  
Insulator Metal Transition ◽  
Wire Method ◽  
Metal State ◽  
Doped Manganites

Abstract The high-purity electron-doped manganites Sm1-xCaxMnO3 nanopowder were prepared by the solid-state reaction method, then the bulk material were obtained through granulation, molding, calcining, grinding and polishing. SCMO nanoparticles with 200 nm were obtained by the sol-gal process. The phase and surface morphology of these materials were characterized by X-ray diffraction and Scanning electron microscope and other experiments. The variable resistivity of the bulk materials were measured by two-wire method in the temperature range of 100–420K. The thermal conductivity was measured by the Laser Flash method. The results show that different doping ratios can change the phase transition temperature of the metal-insulation state. The temperature changed from 0 to 50 °C. The TMI could be regulated to room temperature. When the temperature is high than the TMI, it performs as metal state, on the contrary, it performs as an insulating state.

Enhanced Room Temperature Magnetoresistance in La0.7Ca0.2Sr0.1MnO3/BN Composites

2011 ◽  
Vol 284-286 ◽  
pp. 120-125
Author(s):  
An You Zuo ◽  
Yong Dan Zhu ◽  
Hong Hua Liao ◽  
Juan Jun Tan
Keyword(s):  
Room Temperature ◽  
Boundary Region ◽  
X Ray Diffraction ◽  
Intrinsic Structure ◽  
X Ray ◽  
Tunnelling Effect ◽  
Insulator Metal Transition ◽  
Magnetic Disorder ◽  
Electro Magnetic ◽  
Mr Effect

The effect of added BN on the electro-magnetic properties and enhanced room temperature magnetoresistance in (1-x)La0.7Ca0.2Sr0.1MnO3(LCSMO)+x(BN)composites has been studied systematically. The results of X-ray diffraction (XRD) and SEM show that BN and LCSMO coexist in the composites and BN mainly goes into the grain boundary region without any chemical reaction with LCSMO. The results of electronic measurements show that the intrinsic insulator-metal transition temperature (TP) does not change, which is in accordance with the results for the Curie temperatureTC. It is interesting to note that an enhanced magnetoresisitance (MR) effect for the composites is found over a wide temperature range from low temperature to room temperature in an applied magnetic field of 3 kOe. These phenomena can be explained by considering that BN, which segregated at the grain boundaries or surfaces, does not change the intrinsic structure of LCSMO. We argue that the introduction of BN gives rise to magnetic disorder and hence an enhanced tunnelling effect, which is responsible for the MR enhancement.

SYNTHESIS AND DC CONDUCTIVITY OF PALLADIUM POLYACRYLATE

1993 ◽  
Vol 07 (08) ◽  
pp. 1697-1710
Author(s):  
PARVEEN AKHTAR ◽  
M. PASHA ◽  
FARID A. KHWAJA
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Dc Conductivity ◽  
Heat Treated ◽  
Insulator Metal Transition ◽  
Structural Details ◽  
Exponential Decrease ◽  
Before And After ◽  
Scanning Electron

This papers reports the synthesis and the results of the measurements of dc conductivity of heat treated palladium polyacrylate. Infrared spectra and the scanning electron microscopy of the samples before and after heat treatments are compared in order to reveal their structural details. It is conjectured that at T>38° C molecular aggregates are formed or ion pairing takes place in the material due to the breakdown of the polymer chain in it. The semiconductor-like behavior of the electrical conductivity with the increase of temperature from room temperature to 38°C and thereafter, an exponential decrease in conductivity with further increase in temperature exhibiting a metal-like behaviour show that the material undergoes an insulator-metal transition at this temperature.

Mott Transition Field Effect Transistor: Experimental Results

1999 ◽  
Vol 574 ◽  
Author(s):  
A. G. Schrott ◽  
J. A. Misewich ◽  
B. A. Scott ◽  
A. Gupta ◽  
D. M. Newns ◽  
...  
Keyword(s):  
Room Temperature ◽  
Field Effect Transistor ◽  
Mott Transition ◽  
Oxide Materials ◽  
Gate Electrodes ◽  
Perovskite Materials ◽  
Insulator Metal Transition ◽  
Transition Channel ◽  
Effect Transistor ◽  
P Type

AbstractIn this paper we describe the fabrication of oxide based devices similar in architecture to a conventional FET with source, drain, and gate electrodes and a channel. This distinctive characteristic of our device is the use of a channel material capable of undergoing a field-induced Mott insulator-metal transition at room temperature. Lithographic techniques developed for oxide materials have been combined with pulsed laser deposition of perovskite materials onto single-crystal strontium titanate (STO) substrates to fabricate these devices. Materials chosen for the Mott transition channel include La2CuO4 (LCO) and YBCO, p-type; and Nd2CuO4, n-type.

scholarly journals Voltage-induced insulator-metal transition at room temperature in an anodic porous alumina thin film

2006 ◽  
Vol 38 ◽  
pp. 148-151 ◽  
Author(s):  
S Kato ◽  
S Nigo ◽  
Y Uno ◽  
T Onisi ◽  
G Kido
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Porous Alumina ◽  
Insulator Metal Transition ◽  
Alumina Thin Film ◽  
Anodic Porous Alumina

Carrier transport of extended and localized states in InGaO3(ZnO)5

2004 ◽  
Vol 811 ◽  
Author(s):  
Kenji Nomura ◽  
Hiromichi Ohta ◽  
Kazushige Ueda ◽  
Toshio Kamiya ◽  
Masahiro Hirano ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Carrier Transport ◽  
Room Temperature ◽  
Random Distribution ◽  
Gate Insulator ◽  
Localized States ◽  
Oxide Semiconductor ◽  
Insulator Metal Transition ◽  
Transparent Oxide ◽  
Carrier Transport Properties

ABSTRACTCarrier transport properties and electronic structure of an n-type transparent oxide semiconductor, InGaO3(ZnO)5, were investigated using single-crystalline thin films. Room-temperature Hall mobility strongly depends on carrier concentration, and rapidly increased from ∼ 2 cm2(Vs)-1 to > 10 cm2(Vs)-1 around the carrier concentration (Nth ∼3 × 1018 cm−3. This change is associatedwith insulator-metal transition. These results are explained by a model similar to Anderson localization, in which shallow semi-localized states are formed originating from random distribution of Ga3+ and Zn2+ ions in the intrinsic crystal structure of InGaO3(ZnO)5. The present conclusion suggests that electron densities larger than Nth are necessary to attain high performances in drift carrier devices fabricated using InGaO3(ZnO)5. It was demonstrated that transparent filed-effect transistors exhibited good performances such as a “normally-offcharacteristics”, an on/off current ratios as large as 105 and a field-effect mobility ∼80 cm2(Vs)-1when high-k material, amorphous HfOx, was used as a gate insulator.

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