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Graphite intercalation compounds (GICs) have long been recognized as promising candidates for high-temperature superconductivity by intercalation or charge doping, yet experimental progress has stalled with transition temperatures (Tc)…

We review the theoretical model underpinning the recently reported room-temperature, ambient-pressure superconductivity along line defects on the surface of highly-oriented pyrolytic graphite. The main ingredients for this 1D…

Superconductivity · Physics 2024-09-10 Carlo A. Trugenberger

In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of micro-crystalline graphite. Magnetic field dependent point-contact spectroscopy…

Superconductivity · Physics 2018-05-23 Frank Arnold , Jan Nyeki , John Saunders

It has been claimed that graphite hosts superconductivity at room temperature, although all efforts to isolate it have been vain. Here we report a separation method that uses magnetic field gradients to sort the superconducting from normal…

We report on the magnetic field (0T$ \le B \le 9$T) dependence of the longitudinal thermal conductivity $\kappa(T,B)$ of highly oriented pyrolytic graphite in the temperature range 5 K $\le T\le$ 20 K for fields parallel to the $c-$axis. We…

Strongly Correlated Electrons · Physics 2009-11-10 R. Ocaña , P. Esquinazi , H. Kempa , J. H. S. Torres , Y. Kopelevich

The transport properties of highly oriented pyrolitic graphite (HOPG) and polycrystal graphite have been studied. The electric conductivity of HOPG is several times larger than that of the polycrystal graphite. Along with the large…

Materials Science · Physics 2008-01-23 Zhiming Wang , Feng Xu , Chao Lu , He Zhang , Qingyu Xu , Jinan Zhu

Within the BCS theory of superconductivity we calculate the superconducting gap at zero temperature for metallic hydrogen-graphene system in order to estimate the superconducting critical temperature of quasi two dimensional highly oriented…

Superconductivity · Physics 2009-02-11 N. García , P. Esquinazi

Unique to certain unconventional superconductors is the coexistence of magnetism and superconductivity. We have previously found ferromagnetism and superconductivity in hydrogenated graphitic materials. Herein we present similar as well as…

Superconductivity · Physics 2022-06-20 Nadina Gheorghiu , Charles R. Ebbing , Timothy J. Haugan

Superconducting characteristics such as the Meissner-Ochsenfeld state, screening supercurrents and hysteresis loops of type-II superconductors were observed from the temperature and magnetic field dependences of the magnetic moment, m(T,…

Superconductivity · Physics 2009-11-07 S. Moehlecke , Pei-Chun Ho , M. B. Maple

Pd-metal graphite (Pd-MG) has a layered structure, where each Pd sheet is sandwiched between adjacent graphene sheets. DC magnetization and AC magnetic susceptibility of Pd-MG have been measured using a SQUID magnetometer. Pd-MG undergoes a…

Superconductivity · Physics 2016-08-16 Masatsugu Suzuki , Itsuko S. Suzuki , Jürgen Walter

We have made thermal and electrical transport measurements of uncompressed pyrolytic graphite sheet (uPGS), a mass-produced thin graphite sheet with various thicknesses between 10 and 100 {\mu}m, at temperatures between 2 and 300 K.…

Materials Science · Physics 2017-10-04 Sachiko Nakamura , Daisuke Miyafuji , Takenori Fujii , Tomohiro Matsui , Hiroshi Fukuyama

Bismuth-metal graphite (MG) has a unique layered structure where Bi nanoparticles are encapsulated between adjacent sheets of nanographites. The superconductivity below $T_{c}$ (= 2.48 K) is due to Bi nanoparticles. The Curie-like…

Superconductivity · Physics 2016-08-16 Masatsugu Suzuki , Itsuko S. Suzuki , Robert Lee , Jürgen Walter

Experimental evidence of novel phenomena in hydrogenated graphite fibers is found. An indirect excitonic mechanism is likely leading to a SC state below the temperature Tc = 50 K, where the gap is divergent. Analysis of the gap within the…

Superconductivity · Physics 2023-02-15 Nadina Gheorghiu , Charles R. Ebbing , Timothy J. Haugan

Exposure of highly oriented pyrolytic graphite to bromine vapor gives rise to in-plane charge conductivities which increase monotonically with intercalation time toward values (for ~6 at% Br) that are significantly higher than Cu at…

Materials Science · Physics 2013-05-29 S. Tongay , J. Hwang , D. B. Tanner , H. K. Pal , D. Maslov , A. F. Hebard

Measuring with high precision the electrical resistance of highly ordered natural graphite samples from a Brazil mine, we have identified a transition at $\sim$350~K with $\sim$40~K transition width. The step-like change in temperature of…

This work deals with the intrinsic and extrinsic properties of the graphene layers inside the graphite structure, in particular the influence of defects and interfaces. We discuss the evidence for ballistic transport found in mesoscopic…

Materials Science · Physics 2011-10-13 J. Barzola-Quiquia , A. Ballestar , S. Dusari , P. Esquinazi

We have studied the transport properties of transmission electron microscope (TEM) lamellae obtained from a pyrolytic graphite sample of grade B (SPI-II) with electrical contacts at the edges of the graphene layers. The temperature,…

Superconductivity · Physics 2015-06-23 Ana Ballestar , Pablo Esquinazi , Winfried Böhlmann

We have observed periodically repeated steps in the resistance vs. temperature characteristics of doped Highly Oriented Pyrolytic Graphite and exfoliated doped multi-layer graphene. The observations consist of a series of regularly spaced…

Superconductivity · Physics 2013-07-03 Grover Larkins , Yuriy Vlasov , Kiar Holland

We have studied the magnetic field dependence of the thermal conductivity $\kappa(T,B)$ of highly oriented pyrolytic graphite samples at temperatures 0.2K$ \le T < 10$K and fields 0T$ \le B \le 9$T. The samples show clear deviations from…

Mesoscale and Nanoscale Physics · Physics 2016-08-31 Konstantin Ulrich , Pablo Esquinazi

Temperature and field dependent measurements of the electrical resistance of different natural graphite samples, suggest the existence of superconductivity at room temperature in some regions of the samples. To verify whether…

Superconductivity · Physics 2018-02-02 Markus Stiller , Pablo D. Esquinazi , Jose Barzola-Quiquia , Christian E. Precker