superconductor ceramic compounds has been measured by differential thermal analysis
(DTA) over a large oxygen partial pressure range of five orders of magnitude (2· 10− 5< P
O2< 1 bar). It is shown that the DTA peak and endset temperatures are closer to T m than the
onset temperature. Correct measurement of T m requires low heating rates and
subatmospheric pressure conditions to avoid temperature shifts due to local oxygen …