ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The thermal electromotive force (EMF) generated across a specimen owing to a small nonuniformity in the sample's temperature is used to follow phase transitions in the specimen. As the temperature is scanned, a first-order phase transition yields a sharp S-shaped peak in the EMF versus time, t, and temperature, T(t), curves. A transition to a superconducting state exhibits a sharp drop in EMF as was observed during measurements on YBa2Cu3O7. The dependence of the EMF on time and temperature is calculated for a first-order phase transition. Predictions are confirmed by experiment. This method is therefore useful for detecting phase transition temperatures. A practical feature of this measurement is the ability to precisely calibrate, in situ, the temperature measuring element, e.g., thermometer or thermocouple, when the transition temperature is already known.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.347305
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