Specific Heat of YBa2Cu3O7-delta, 0 <=delta <= 0.2: Concentrations of paramagnetic centers and values of other parameters as functions of delta

The concentrations of paramagnetic centers and the values of other paramete rs, including the Debye temperature and the coefficient of the zero-field, temperature-proportional term, are reported as functions of delta. The conc entration of paramagnetic centers does increase with increasing delta but, in striking contrast with the widely held expectation that the increase wou ld be comparable to the increase in the concentration of O vacancies, it is as much as 2 orders of magnitude smaller. A new expression for the specifi c heat that takes into account the presence of spin-2 as well as spin-1/2 p aramagnetic centers gives an accurate representation of the experimental da ta.[S0031-9007(99)08491-4].