Premium
Size effects in the conduction electron spin resonance of anthracite and higher anthraxolite
Author(s) -
Tadyszak Krzysztof,
Strzelczyk Roman,
Coy Emerson,
Maćkowiak Mariusz,
AugustyniakJabłokow Maria A.
Publication year - 2016
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4373
Subject(s) - chemistry , electron paramagnetic resonance , thermal conduction , electron , resonance (particle physics) , condensed matter physics , conductivity , spins , paramagnetism , electrical resistivity and conductivity , spectral line , nuclear magnetic resonance , asymmetry , atomic physics , materials science , physics , quantum mechanics , astronomy , composite material
Electron paramagnetic resonance spectroscopy of conduction electrons, i.e. Conduction Electron Spin Resonance (CESR), is a powerful tool for studies of carbon samples. Conductive samples cause additional effects in CESR spectra that influence the shape and intensity of the signals. In cases where conduction electrons play a dominant role, whilst the influence of localized paramagnetic centres is small or negligible, the effects because of the spins on conduction electrons will dominate the spectra. It has been shown that for some ratios of the bulk sample sizes ( d ) to the skin depth ( δ ), which depend on the electrical conductivity, additional size effects become visible in the line asymmetry parameter A /| B |, which is the ratio of the maximum to the absolute, minimum value of the resonance signal. To study these effects the electrical direct current–conductivity and CESR measurements are carried out for two amorphous bulk coal samples of anthracite and a higher anthraxolite. The observed effects are described and discussed in terms of the Dyson theory. Copyright © 2015 John Wiley & Sons, Ltd.