Specific heat of soft carbons between 0.4 and 4.5°K—III
1976; Elsevier BV; Volume: 14; Issue: 4 Linguagem: Inglês
10.1016/0008-6223(76)90110-x
ISSN1873-3891
Autores Tópico(s)Ion-surface interactions and analysis
ResumoA more extensive and thorough investigation of the specific heat of two series of soft carbons heattreated to various temperatures from 600 to 3000°C and of a series of samples of an AS graphite neutron irradiated to various doses, was carried out. In particular, efforts were concentrated on mapping out the exact shape and position of the low temperature peak. A spectroscopic analysis of the impurity content of several of the investigated samples was made and the concentrations of localized spins were determined for all samples by means of the ESR technique. The most important result of this study is, that as the temperature is lowered, a fraction of all localized spins condenses at around 0.65°K into an antiferromagnetic phase, the fraction varying from about 2% for lowest up to 20% or more for the highest spin concentrations. An interpretation of the results is suggested and some other questions and difficulties brought out by this work are discussed.
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