Defects and charge transport in Mn-doped K0.5Na0.5NbO3 ceramics

2015 ◽  
Vol 17 (37) ◽  
pp. 24403-24411 ◽  
Author(s):  
Muhammad Asif Rafiq ◽  
Alexander Tkach ◽  
Maria Elisabete Costa ◽  
Paula Maria Vilarinho
Keyword(s):  
Charge Transport ◽  
Hysteresis Loop ◽  
Grain Boundaries ◽  
High Temperatures ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Hole Transport ◽  
Mn Doping ◽  
Mn Doped ◽  
Temperature Conduction

KNN room-temperature conduction is associated with hole transport and can be suppressed by Mn-doping; a less leaky hysteresis loop is obtained. At high temperatures conduction is dominated by ionized oxygen vacancies motion. From grains and grain-boundaries resistance oxygen vacancies in KNN and Mn-doped KNN ceramics are mainly located at grain-boundaries.

Hydrothermal Synthesis and Ferromagnetic Properties of Mn-Doped Na0.5Bi0.5TiO3 Crystals

2011 ◽  
Vol 311-313 ◽  
pp. 2110-2113 ◽  
Author(s):  
Yong Gang Wang ◽  
Yu Jiang Wang
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Room Temperature ◽  
Doping Concentration ◽  
Multiferroic Materials ◽  
Ferromagnetic Properties ◽  
Mn Doping ◽  
Pure Phase ◽  
Mn Doped

Pure phase Mn-doped Na0.5Bi0.5TiO3 crystals were successfully synthesized by a hydrothermal method. Magnetic loops measured at room temperature indicate that ferromagnetism can be obtained in Mn-doped Na0.5Bi0.5TiO3 crystals, and the magnetism of Na0.5Bi0.5TiO3 crystals can be controlled by adjusting Mn doping concentration. The magnetism of the Mn-doped Na0.5Bi0.5TiO3 crystals varied from diamagnetism, ferromagnetism, and paramagnetic on increasing Mn doping concentration from 0 to 30mol%. The results showed in this study may provide an approach to widely exploring more multiferroic materials.

Charge Transport in Pentacene Thin Film Transistors

2001 ◽  
Vol 665 ◽  
Author(s):  
J. H. Schön ◽  
L. D. Buchholz ◽  
Ch. Kloc ◽  
B. Batlogg
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Charge Transport ◽  
Grain Boundaries ◽  
Thin Film Transistors ◽  
Room Temperature ◽  
Nanocrystalline Material ◽  
Hole Mobility ◽  
Grain Sizes

ABSTRACTThe charge transport properties in polycrystalline pentacene thin film transistors is investigated. A potential barrier is formed at grain boundaries due charged trapping states. The influence of such grain boundaries on the hole mobility of the devices is analyzed for different grain sizes, trap concentrations, and carrier densities. The results reveal that room temperature mobilities exceeding 0.5 cm2/Vs can be obtained in thin films with large grains as well as in nanocrystalline material. Consequently, single crystal device limits can be reached also by polycrystalline pentacene thin film transistors.

scholarly journals Effect of Mn Doping on The Structural, Optical, Magnetic Properties and Antibacterial Activity of ZnO Nanospheres

2021 ◽  
Author(s):  
EBENEZAR JEYASINGH ◽  
Kelvin Adaikalam Charles ◽  
Pandiyarajan Thangaraj ◽  
Karthikeyan Chandrasekaran ◽  
Mangalaraja Ramalinga Viswanathan
Keyword(s):  
Zinc Oxide ◽  
Oxygen Vacancies ◽  
Average Particle Size ◽  
Antibacterial Properties ◽  
Ferromagnetic Phase ◽  
Average Particle ◽  
Zno Nps ◽  
Mn Doping ◽  
Doped Zno ◽  
Mn Doped

Abstract In this work, a systematic study of structural, optical, magnetic and antibacterial properties of Mn doped ZnO has been investigated. Zinc oxide (ZnO) and Mn2+ doped zinc oxide (ZnMnO) nanoparticles (NPs) were prepared through co-precipitation method. The X-ray diffraction studies confirmed that the synthesize nanoparticles did not modify the crystal structure upon Mn doping, but the microstructural parameters were changed considerably while increasing the concentration of Mn dopant. The HRTEM images showed that the ZnO NPs were exhibited nanospheres like morphology and a reduction in the average particle size from 41 nm to 33 nm were observed upon Mn2+ doping. The elemental composition of Zn, Mn and O atoms were identified by EDAX spectra. The Zn-O stretching bands were observed at 539 and 525cm-1 in the FTIR spectra and, the zinc and oxygen vacancies defects were confirmed by PL spectra. From the UV-Vis spectra, the band gap was estimated as 2.7 eV for pure and 2.9 eV for Mn doped ZnO NPs. The Mn doped ZnO NPs showed greater antibacterial effect than the pure ZnO NPs. The magnetization measurements for Mn doped ZnO samples under room temperature ferromagnetism (RTFM) showed the ferromagnetic phase that could originated from the interactions between Mn2+ ions and oxygen vacancies and the defects incorporated in the ZnO matrix.

Bandgap tuning in ZnO thin films and enhanced n-type properties through Mn doping synthesized by a simple spray pyrolysis

2021 ◽  
pp. 2150155
Author(s):  
Md. Khorshed Alam ◽  
Mehnaz Sharmin ◽  
Jiban Podder
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Room Temperature ◽  
Visible Region ◽  
Zno Thin Films ◽  
Bandgap Energy ◽  
Chemical Compositions ◽  
Mn Doping ◽  
X Ray ◽  
Mn Doped

Undoped and manganese (Mn)-doped zinc oxide (ZnO) thin films have been deposited onto glass substrates at 300[Formula: see text]C using a low cost spray pyrolysis technique. Structural, optical and electrical properties of the as-deposited films have been investigated. Scanning electron microscopy images show the existence of clusters with well-defined nucleation centers consisting of highly dense ganglia-like fibers over a large area around the nucleation center. Chemical compositions of the ZnO and Mn-doped ZnO thin films are studied by using energy dispersive X-ray (EDX) analysis. X-ray diffraction spectra depict that the films have polycrystalline wurtzite structure. The average crystallite sizes are calculated in the range of 8–16 nm by Williamson–Hall method and found in good agreement with Scherer method. Optical transmittance of the films is about 80% in the visible region. Bandgap energy is tuned to 2.83 eV from 3.10 eV with increasing Mn doping. Electrical resistivity at room-temperature decreases significantly with increasing Mn doping as well as increasing temperature from 300–440 K. The activation energies in the temperature ranges 300–350 K and 350–440 K are found to be in the range of 0.25–0.16 eV and 0.35–0.59 eV, respectively. Hall Effect measurements show that the thin films have negative Hall co-efficient indicating [Formula: see text]-type conductivity at room-temperature. Carrier concentration is found to be of the order of 10[Formula: see text] cm[Formula: see text].

Extreme Room Temperature Compression and Bending in Ferroelectric Oxide Pillars

2021 ◽  
Author(s):  
Ying Liu ◽  
Xiangyuan Cui ◽  
Ranming Niu ◽  
Shujun Zhang ◽  
Xiaozhou Liao ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Ceramic Materials ◽  
Perovskite Oxide ◽  
High Concentration ◽  
Bending Tests ◽  
Ionic Bonds ◽  
Order Of Magnitude ◽  
Mn Doped

Abstract Plastic deformation in ceramic materials is normally only observed in nanometre-sized samples. However, we have observed unprecedented levels of plasticity (>50% plastic strain) and excellent elasticity (6% elastic strain) in perovskite oxide Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT), under compression along <100>pc pillars up to 2.1 μm in diameter. The extent of this deformation is much higher than has previously been reported for ceramic materials, and the sample size at which plasticity is observed is almost an order of magnitude larger. Bending tests also revealed over 8% flexural strain. Plastic deformation occurred by slip along {110} <110>. Calculations indicate that the resulting strain gradients will give rise to extreme flexoelectric polarization. First principles models predict that a high concentration of oxygen vacancies (Vo) weaken the covalent/ionic bonds, giving rise to the unexpected plasticity. Mechanical testing on Vo-rich Mn-doped PIN-PMN-PT confirmed this prediction. These findings will facilitate the design of plastic ceramic materials and the development of flexoelectric-based nano-electromechanical systems.

An insight into the origin of room-temperature ferromagnetism in SnO2 and Mn-doped SnO2 quantum dots: an experimental and DFT approach

2018 ◽  
Vol 20 (9) ◽  
pp. 6500-6514 ◽  
Author(s):  
Dhamodaran Manikandan ◽  
D. W. Boukhvalov ◽  
S. Amirthapandian ◽  
I. S. Zhidkov ◽  
A. I. Kukharenko ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Mn Doped ◽  
Insight Into ◽  
Multiple Configurations

Oxygen vacancies and multiple configurations of Mn (Mn2+ and Mn3+) might be the cause of the observed room-temperature ferromagnetism in SnO2 QDs.

scholarly journals Significantly reduced leakage current density in Mn-doped BiFeO3 thin films deposited using spin coating technique

2021 ◽  
Vol 2070 (1) ◽  
pp. 012088
Author(s):  
Waseem Ahmad Wani ◽  
Nilofar Naaz ◽  
B. Harihara Venkataraman ◽  
Souvik Kundu ◽  
Kannan Ramaswamy
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Indium Tin Oxide ◽  
Oxygen Vacancies ◽  
Oxide Glass ◽  
Mn Doping ◽  
X Ray ◽  
Mn Doped

Abstract BiFeO3 (BFO) and Mn-doped BFO thin films are prepared on indium tin oxide/glass substrates using wet chemical deposition technique. The role of Mn defects (3% to 10%) on the leakage current density and other physical properties of BFO thin film devices is investigated. The X-ray diffraction patterns confirm the single-phase formation of rhombohedrally distorted BFO thin films. The scanning electron microscopy images approve uniform and crack-free film depositions, which is of great importance to the practical device applications of such materials. The oxidation states are determined by X-ray photoelectron spectroscopy (XPS). These XPS results reveal the presence of multiple valence states of Fe ions (Fe2+, Fe3+) and Mn (Mn3+, Mn4+) ions, which play a decisive role in determining the leakage current density. However, the Mn-doping at the Fe site in BFO reduces oxygen vacancies and Fe2+ states, hence suppressing the leakage current density. The leakage current density is reduced by three orders of magnitude (10−4 – 10−7) A/cm2, upon Mn-doping as clearly demonstrated by J-V characteristics. These results indicate that the primary contributors to the conduction in BFO based thin films are oxygen vacancies and the Fe2+ states in these devices.

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