A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition
We present micro-calorimetric specific heat measurements on different multiwall carbon nanotubes of large outer diameter, as a function of temperature in the range 10-120 K. A clear anomaly at 60 K with the shape of a peak is present in two of the samples, and both the height and the characteristic...
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todo:paper_00086223_v48_n2_p525_Jorge2023-10-03T14:07:41Z A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition Jorge, G.A. Bekeris, V. Escobar, M.M. Goyanes, S. Zilli, D. Cukierman, A.L. Candal, R.J. Degrees of freedom (mechanics) Order disorder transitions Specific heat Thermal variables measurement Yarn Adsorbed gas Characteristic temperature Molecular systems Multiwall nanotubes Orientational orderings Outer diameters Thermal hysteresis Multiwalled carbon nanotubes (MWCN) We present micro-calorimetric specific heat measurements on different multiwall carbon nanotubes of large outer diameter, as a function of temperature in the range 10-120 K. A clear anomaly at 60 K with the shape of a peak is present in two of the samples, and both the height and the characteristic temperature of the peak are independent of magnetic field and do not exhibit thermal hysteresis, discarding magnetic degrees of freedom related to Fe seeds or contributions from adsorbed gases. These features suggest that the anomaly may be caused by a structural change. As the anomaly is also unaffected by induced intertube disorder, it may be related with a melting of orientational dislocations of individual tubes within multiwall nanotubes, an effect that was theoretically predicted to occur in carbon nanotubes and represents a distinctive feature of asymmetric molecular systems. © 2009 Elsevier Ltd. All rights reserved. Fil:Jorge, G.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Bekeris, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Escobar, M.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Goyanes, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Cukierman, A.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Candal, R.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00086223_v48_n2_p525_Jorge |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Degrees of freedom (mechanics) Order disorder transitions Specific heat Thermal variables measurement Yarn Adsorbed gas Characteristic temperature Molecular systems Multiwall nanotubes Orientational orderings Outer diameters Thermal hysteresis Multiwalled carbon nanotubes (MWCN) |
| spellingShingle |
Degrees of freedom (mechanics) Order disorder transitions Specific heat Thermal variables measurement Yarn Adsorbed gas Characteristic temperature Molecular systems Multiwall nanotubes Orientational orderings Outer diameters Thermal hysteresis Multiwalled carbon nanotubes (MWCN) Jorge, G.A. Bekeris, V. Escobar, M.M. Goyanes, S. Zilli, D. Cukierman, A.L. Candal, R.J. A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| topic_facet |
Degrees of freedom (mechanics) Order disorder transitions Specific heat Thermal variables measurement Yarn Adsorbed gas Characteristic temperature Molecular systems Multiwall nanotubes Orientational orderings Outer diameters Thermal hysteresis Multiwalled carbon nanotubes (MWCN) |
| description |
We present micro-calorimetric specific heat measurements on different multiwall carbon nanotubes of large outer diameter, as a function of temperature in the range 10-120 K. A clear anomaly at 60 K with the shape of a peak is present in two of the samples, and both the height and the characteristic temperature of the peak are independent of magnetic field and do not exhibit thermal hysteresis, discarding magnetic degrees of freedom related to Fe seeds or contributions from adsorbed gases. These features suggest that the anomaly may be caused by a structural change. As the anomaly is also unaffected by induced intertube disorder, it may be related with a melting of orientational dislocations of individual tubes within multiwall nanotubes, an effect that was theoretically predicted to occur in carbon nanotubes and represents a distinctive feature of asymmetric molecular systems. © 2009 Elsevier Ltd. All rights reserved. |
| format |
JOUR |
| author |
Jorge, G.A. Bekeris, V. Escobar, M.M. Goyanes, S. Zilli, D. Cukierman, A.L. Candal, R.J. |
| author_facet |
Jorge, G.A. Bekeris, V. Escobar, M.M. Goyanes, S. Zilli, D. Cukierman, A.L. Candal, R.J. |
| author_sort |
Jorge, G.A. |
| title |
A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| title_short |
A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| title_full |
A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| title_fullStr |
A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| title_full_unstemmed |
A specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| title_sort |
specific heat anomaly in multiwall carbon nanotubes as a possible sign of orientational order-disorder transition |
| url |
http://hdl.handle.net/20.500.12110/paper_00086223_v48_n2_p525_Jorge |
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1807320110000504832 |