Thermal conductance of highly oriented pyrolytic graphite along the c-direction at very low temperatures including magnetic field effects
✍ Scribed by B. Kastelein; R.D. Van Bergen; H. Postma; H.C. Meijer; F. Mathu
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 668 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
The thermal conductance of several samples of highly oriented pyrolytic graphite (HOPG) has been measured between 20 mK and 700 mK in zero magnetic field and in external magnetic fields up to 1.5 T, directed parallel and perpendicular to the c-axis, respectively. The results for thicker samples (230 and 326 pm), that were cleaved from bulk HOPG, agree with literature values, reported down to 70 mK. Very thin samples (thickness 14 pm and 30 pm), that were peeled off from bulk HOPG, show a reduction of the thermal conductance by more than one order of magnitude, which is ascribed to the preparation method. The carrier contribution has been determined at 25,50,100, and 500 mK by observing the reduction of the thermal conductance as a function of external magnetic field. The maximum reduction at 25 mK is 40% when the magnetic field is directed parallel, and 8% when the magnetic field is perpendicular to the graphite c-axis.