Identification of a possible superconducting transition above room temperature in natural graphite crystals
Measuring with high precision the electrical resistance of highly ordered natural graphite samples from a Brazil mine, we have identified a transition at ∼350 K with ∼40 K transition width. The step-like change in temperature of the resistance, its magnetic irreversibility and time dependence after...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2016-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/18/11/113041 |
| _version_ | 1797750916812636160 |
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| author | Christian E Precker Pablo D Esquinazi Ana Champi José Barzola-Quiquia Mahsa Zoraghi Santiago Muiños-Landin Annette Setzer Winfried Böhlmann Daniel Spemann Jan Meijer Tom Muenster Oliver Baehre Gert Kloess Henning Beth |
| author_facet | Christian E Precker Pablo D Esquinazi Ana Champi José Barzola-Quiquia Mahsa Zoraghi Santiago Muiños-Landin Annette Setzer Winfried Böhlmann Daniel Spemann Jan Meijer Tom Muenster Oliver Baehre Gert Kloess Henning Beth |
| author_sort | Christian E Precker |
| collection | DOAJ |
| description | Measuring with high precision the electrical resistance of highly ordered natural graphite samples from a Brazil mine, we have identified a transition at ∼350 K with ∼40 K transition width. The step-like change in temperature of the resistance, its magnetic irreversibility and time dependence after a field change, consistent with trapped flux and flux creep, and the partial magnetic flux expulsion obtained by magnetization measurements, suggest the existence of granular superconductivity below 350 K. The zero-field virgin state can only be reached again after zero field cooling the sample from above the transition. Paradoxically, the extraordinarily high transition temperature we found for this and several other graphite samples is the reason why this transition remained undetected so far. The existence of well ordered rhombohedral graphite phase in all measured samples has been proved by x-rays diffraction measurements, suggesting its interfaces with the Bernal phase as a possible origin for the high-temperature superconductivity, as theoretical studies predicted. The localization of the granular superconductivity at these two dimensional interfaces prevents the observation of a zero resistance state or of a full Meissner state. |
| first_indexed | 2024-03-12T16:39:46Z |
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| id | doaj.art-b2a85cf423224b478051c1a77d6f760b |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:39:46Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-b2a85cf423224b478051c1a77d6f760b2023-08-08T14:35:28ZengIOP PublishingNew Journal of Physics1367-26302016-01-01181111304110.1088/1367-2630/18/11/113041Identification of a possible superconducting transition above room temperature in natural graphite crystalsChristian E Precker0Pablo D Esquinazi1Ana Champi2José Barzola-Quiquia3Mahsa Zoraghi4Santiago Muiños-Landin5Annette Setzer6Winfried Böhlmann7Daniel Spemann8Jan Meijer9Tom Muenster10Oliver Baehre11Gert Kloess12Henning Beth13Division of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyCentro de Ciências Naturais e Humanas, Universidade Federal do ABC , 09210-170, Santo André, São Paulo, BrazilDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Superconductivity and Magnetism, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Nuclear Solid State Physics, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyDivision of Nuclear Solid State Physics, Institut für Experimentelle Physik II, Universität Leipzig , Linnéstraße 5, D-04103 Leipzig, GermanyInstitut für Mineralogie, Kristallographie und Materialwissenschaft, Fakultät für Chemie und Mineralogie, Universität Leipzig , Scharnhorststraße 20, D-04275 Leipzig, GermanyInstitut für Mineralogie, Kristallographie und Materialwissenschaft, Fakultät für Chemie und Mineralogie, Universität Leipzig , Scharnhorststraße 20, D-04275 Leipzig, GermanyInstitut für Mineralogie, Kristallographie und Materialwissenschaft, Fakultät für Chemie und Mineralogie, Universität Leipzig , Scharnhorststraße 20, D-04275 Leipzig, GermanyGolden Bowerbird Pty Ltd. , 32 Alidenes Rd., 2482 Mullumbimby, Nsw AustraliaMeasuring with high precision the electrical resistance of highly ordered natural graphite samples from a Brazil mine, we have identified a transition at ∼350 K with ∼40 K transition width. The step-like change in temperature of the resistance, its magnetic irreversibility and time dependence after a field change, consistent with trapped flux and flux creep, and the partial magnetic flux expulsion obtained by magnetization measurements, suggest the existence of granular superconductivity below 350 K. The zero-field virgin state can only be reached again after zero field cooling the sample from above the transition. Paradoxically, the extraordinarily high transition temperature we found for this and several other graphite samples is the reason why this transition remained undetected so far. The existence of well ordered rhombohedral graphite phase in all measured samples has been proved by x-rays diffraction measurements, suggesting its interfaces with the Bernal phase as a possible origin for the high-temperature superconductivity, as theoretical studies predicted. The localization of the granular superconductivity at these two dimensional interfaces prevents the observation of a zero resistance state or of a full Meissner state.https://doi.org/10.1088/1367-2630/18/11/113041graphiteinterfaces2D superconductivity74.10.+v74.70.Wz74.78.-w |
| spellingShingle | Christian E Precker Pablo D Esquinazi Ana Champi José Barzola-Quiquia Mahsa Zoraghi Santiago Muiños-Landin Annette Setzer Winfried Böhlmann Daniel Spemann Jan Meijer Tom Muenster Oliver Baehre Gert Kloess Henning Beth Identification of a possible superconducting transition above room temperature in natural graphite crystals New Journal of Physics graphite interfaces 2D superconductivity 74.10.+v 74.70.Wz 74.78.-w |
| title | Identification of a possible superconducting transition above room temperature in natural graphite crystals |
| title_full | Identification of a possible superconducting transition above room temperature in natural graphite crystals |
| title_fullStr | Identification of a possible superconducting transition above room temperature in natural graphite crystals |
| title_full_unstemmed | Identification of a possible superconducting transition above room temperature in natural graphite crystals |
| title_short | Identification of a possible superconducting transition above room temperature in natural graphite crystals |
| title_sort | identification of a possible superconducting transition above room temperature in natural graphite crystals |
| topic | graphite interfaces 2D superconductivity 74.10.+v 74.70.Wz 74.78.-w |
| url | https://doi.org/10.1088/1367-2630/18/11/113041 |
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