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Full-Text Articles in Physical Sciences and Mathematics

Ferromagnetism Of Magnetically Doped Topological Insulators In Crxbi2− Xte3 Thin Films, Yan Ni, Z. Zhang, Ikenna C. Nlebedim, M. Ravi Hadimani, Gary L. Tuttle, David C. Jiles Jun 2017

Ferromagnetism Of Magnetically Doped Topological Insulators In Crxbi2− Xte3 Thin Films, Yan Ni, Z. Zhang, Ikenna C. Nlebedim, M. Ravi Hadimani, Gary L. Tuttle, David C. Jiles

Gary Tuttle

We investigated the effect of magnetic doping on magnetic and transport properties of Bi2Te3thin films. CrxBi2−xTe3 thin films with x = 0.03, 0.14, and 0.29 were grown epitaxially on mica substrate with low surface roughness (∼0.4 nm). It is found that Cr is an electron acceptor in Bi2Te3 and increases the magnetization of CrxBi2−xTe3. When x = 0.14 and 0.29,ferromagnetism appears in CrxBi2−xTe3 thin films, where anomalous Hall effect and weak localization of magnetoconductance were observed. The Curie temperature, coercivity, and remnant Hall resistance of thin films increase with increasing Cr concentration. The Arrott-Noakes plot demonstrates that the critical mechanism …


Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson Mar 2017

Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson

Thomas E. Wilson

Progress is described in experiments to generate coherent terahertz acoustic phonons in silicon doping superlattices by the resonant absorption of nanosecond-pulsed far-infrared laser radiation. Future experiments are proposed that would use the superlattice as a transducer in a terahertz cryogenic acoustic reflection microscope with sub-nanometer resolution.


Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal Apr 2015

Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal Apr 2015

Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal Apr 2015

Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Applications Of High Throughput (Combinatorial) Methodologies To Electronic, Magnetic, Optical, And Energy-Related Materials, Martin L. Green, Ichiro Takeuchi, Jason R. Hattrick-Simpers Mar 2015

Applications Of High Throughput (Combinatorial) Methodologies To Electronic, Magnetic, Optical, And Energy-Related Materials, Martin L. Green, Ichiro Takeuchi, Jason R. Hattrick-Simpers

Jason R. Hattrick-Simpers

High throughput (combinatorial) materials science methodology is a relatively new research paradigm that offers the promise of rapid and efficient materials screening, optimization, and discovery. The paradigm started in the pharmaceutical industry but was rapidly adopted to accelerate materials research in a wide variety of areas. High throughput experiments are characterized by synthesis of a “library” sample that contains the materials variation of interest (typically composition), and rapid and localized measurement schemes that result in massive data sets. Because the data are collected at the same time on the same “library” sample, they can be highly uniform with respect to …


Correlation Between Doping Induced Disorder And Superconducting Properties In Carbohydrate Doped Mgb2, Jung Ho Kim, S X. Dou, Sangjun Oh, M Jercinovic, E Babic, T Nakane, Hiroaki Kumakura Jun 2013

Correlation Between Doping Induced Disorder And Superconducting Properties In Carbohydrate Doped Mgb2, Jung Ho Kim, S X. Dou, Sangjun Oh, M Jercinovic, E Babic, T Nakane, Hiroaki Kumakura

Shi Xue Dou

A comprehensive study of the effects of carbohydrate doping on the superconductivity of MgB2 has been conducted. In accordance with the dual reaction model, more carbon substitution is achieved at lower sintering temperature. As the sintering temperature is lowered, lattice disorder is increased. Disorder is an important factor determining the transition temperature for the samples studied in this work, as evidenced from the correlations among the lattice strain, the resistivity, and the transition temperature. It is further shown that the increased critical current density in the high field region can be understood by a recently-proposed percolation model [M. Eisterer et …


Carbohydrate Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, Jung Ho Kim, Sihai Zhou, Md S. Hossain, Alexey V. Pan, S X. Dou Jun 2013

Carbohydrate Doping To Enhance Electromagnetic Properties Of Mgb2 Superconductors, Jung Ho Kim, Sihai Zhou, Md S. Hossain, Alexey V. Pan, S X. Dou

Shi Xue Dou

The effect of carbohydrate doping on lattice parameters, microstructure, Tc, Jc, Hirr, and Hc2 of MgB2 has been studied. In this work the authors used malic acid as an example of carbohydrates as an additive to MgB2. The advantages of carbohydrate doping include homogeneous mixing of precursor powders, avoidance of expansive nanoadditives, production of highly reactive C, and significant enhancement in Jc, Hirr, and Hc2 of MgB2, compared to undoped samples. The Jc for MgB2+30 wt% C4H6O5 sample was increased by a factor of 21 at 5 K and 8 T without degradation of self-field Jc.


Enhancement Of The In-Field Jc Of Mgb2 Via Sicl4 Doping, Xiaolin Wang, S X. Dou, Md S. Hossain, Zhenxiang Cheng, X.Z Liao, Shaban R. Ghorbani, Qiwen Yao, Jung Ho Kim, Tania M. Silver Jun 2013

Enhancement Of The In-Field Jc Of Mgb2 Via Sicl4 Doping, Xiaolin Wang, S X. Dou, Md S. Hossain, Zhenxiang Cheng, X.Z Liao, Shaban R. Ghorbani, Qiwen Yao, Jung Ho Kim, Tania M. Silver

Shi Xue Dou

We present the following results. (1) We introduce a doping source for MgB2, liquid SiCl4, which is free of C, to significantly enhance the irreversibility field (Hirr), the upper critical field (Hc2), and the critical current density (Jc) with a little reduction in the critical temperature (Tc). (2) Although Si can not be incorporated into the crystal lattice, a significant reduction in the a-axis lattice parameter was found, to the same extent as for carbon doping. (3) Based on the first-principles calculation, it is found that it is reliable to estimate the C concentration just from the reduction in the …