Nonharmonic phonons in MgB2 at elevated temperatures
نویسندگان
چکیده
N. D. Markovskiy,1 J. A. Muñoz,1 M. S. Lucas,2 Chen W. Li,1 O. Delaire,2 M. B. Stone,2 D. L. Abernathy,2 and B. Fultz1 1California Institute of Technology, Department of Applied Physics and Materials Science, Pasadena, California 91125, USA 2Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, USA (Received 21 November 2010; revised manuscript received 11 March 2011; published 4 May 2011)
منابع مشابه
Effect of pressure on the superconducting transition temperature of doped and neutron-damaged MgB2
Measurements of the superconducting transition temperatures for Al-doped, Cdoped and neutron-damaged-annealed MgB2 samples under pressure up to ∼ 8 kbar are presented. The dTc/dP values change systematically with the decrease of the ambient pressure Tc in a regular fashion. The evolution of the pressure derivatives can be understood assuming that the change in phonon spectrum is a dominant cont...
متن کاملNonharmonic phonons in α-iron at high temperatures
L. Mauger,1 M. S. Lucas,2 J. A. Muñoz,1 S. J. Tracy,1 M. Kresch,3 Yuming Xiao,4 Paul Chow,4 and B. Fultz1 1California Institute of Technology, W. M. Keck Laboratory 138-78, Pasadena, California 91125, USA 2Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, USA 3Marft, Inc., 101 Irene Court, Belmont, California 94002, USA 4HPCAT, Geophysical Laboratory, Carnegie Institute of Washin...
متن کاملEnhancing superconducting properties of MgB2 pellets by addition of amorphous magnetic Ni-Co-B nanoparticles
Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density ( Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher impr...
متن کاملسازوکار میخکوبش و انرژی فعال سازی در ابررسانای MgB2 آلاییده به مالیک اسید
Fulx-pinning mechanism and activation energy of MgB2 doped with 10 wt % malic- acid has been investigated by measurement of critical current density and resistivity as a function of magnetic fields and temperatures. The field dependence of the critical current density, Jc(B), was analyzed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bun...
متن کاملLarge anisotropic normal-state magnetoresistance in clean MgB2 thin films.
We report a large normal-state magnetoresistance with temperature-dependent anisotropy in very clean epitaxial MgB2 thin films (residual resistivity much smaller than 1 microOmega cm) grown by hybrid physical-chemical vapor deposition. The magnetoresistance shows a complex dependence on the orientation of the applied magnetic field, with a large magnetoresistance (Delta(rho)/(rho)0=136%) observ...
متن کامل