Importance of coherence length in explaining superconducting behaviour of cuprate superconductors

It has been argued that, in explaining their data on cuprate superconductors some authors appear to have considered incorrect variation of the coherence length with impurity concentration. Considering two cases from the existing literature, namely the explanation of critical current density of Pr doped YBa2Cu3O7 samples and the explanation of the penetration depth of Fe doped YBa2Cu3O7 samples it has been clarified that, these proposed explanations may be misleading. (author)