TY - JOUR
T1 - Enhancing the superconducting temperature of MgB2 by SWCNT dilution
AU - Ma, Danhao
AU - Jayasingha, Ruwantha
AU - Hess, Dustin T.
AU - Adu, Kofi W.
AU - Sumanasekera, Gamini U.
AU - Terrones, Mauricio
N1 - Funding Information:
This work is supported by the Pennsylvania State University, Altoona College Undergraduate Research Program and the Pennsylvania State University Materials Research Institute. The corresponding author thanks Prof. Zimmerman (Penn State Altoona) for his meaningful comments, and Mr. Mark Hoover, Mr. Gregory Hatch and Mrs. Lynn Dalby (The Lab support staff, Penn State Altoona).
PY - 2014
Y1 - 2014
N2 - We report, for the first time, an increase in the superconducting critical temperature, TC of commercial "dirty" MgB2 by a nonsubstitutional hole-doping of the MgB2 structure using minute, single-wall carbon nanotube (SWCNT) inclusions. We varied the SWCNTs concentration from 0.05 wt% to 5 wt% and investigated the temperature-dependent resistivity from 10 K to 300 K. We used micro-Raman spectroscopy, field-emission scanning electron microscopy, and X-ray diffraction to analyze the interfacial interactions between the SWCNTs and the MgB2 grains. We obtained an increase in TC from 33.0 to 37.8 K (ΔTC+=4.8K), which is attributed to charge transfer from the MgB2 structure to the SWCNT structure. The charge transfer phenomenon is confirmed by micro-Raman analysis of the phonon states of the SWCNT tangential band frequency in the composites. We determined the charge transfer per carbon atom to be 0.0023/C, 0.0018/C and 0.0008/C for 0.05 wt%, 0.5 wt% and 5 wt% SWCNT inclusions, respectively, taking into account the contributions from the softening of the lattice constant and the nonadiabatic (dynamic) effects at the Fermi level. This report provides an experimental, alternative pathway to hole-doping of MgB2 without appealing to chemical substitution.
AB - We report, for the first time, an increase in the superconducting critical temperature, TC of commercial "dirty" MgB2 by a nonsubstitutional hole-doping of the MgB2 structure using minute, single-wall carbon nanotube (SWCNT) inclusions. We varied the SWCNTs concentration from 0.05 wt% to 5 wt% and investigated the temperature-dependent resistivity from 10 K to 300 K. We used micro-Raman spectroscopy, field-emission scanning electron microscopy, and X-ray diffraction to analyze the interfacial interactions between the SWCNTs and the MgB2 grains. We obtained an increase in TC from 33.0 to 37.8 K (ΔTC+=4.8K), which is attributed to charge transfer from the MgB2 structure to the SWCNT structure. The charge transfer phenomenon is confirmed by micro-Raman analysis of the phonon states of the SWCNT tangential band frequency in the composites. We determined the charge transfer per carbon atom to be 0.0023/C, 0.0018/C and 0.0008/C for 0.05 wt%, 0.5 wt% and 5 wt% SWCNT inclusions, respectively, taking into account the contributions from the softening of the lattice constant and the nonadiabatic (dynamic) effects at the Fermi level. This report provides an experimental, alternative pathway to hole-doping of MgB2 without appealing to chemical substitution.
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U2 - 10.1016/j.physc.2013.09.017
DO - 10.1016/j.physc.2013.09.017
M3 - Article
AN - SCOPUS:84887977837
SN - 0921-4534
VL - 497
SP - 43
EP - 48
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
ER -