Capacitance temperature sensor using epitaxial SrTiO3 film with a single-crystal-like behavior

A parallel capacitor of epitaxially grown YBa2Cu3O7−δ/SrTiO3/YBa2Cu3O7−δ was fabricated by a chemical mechanical planarization method and its characteristics as a capacitance thermometer were investigated. The capacitance, temperature sensitivity, and dimensionless temperature sensitivity of the elements were found to be 1.7 nF, 10 pF/K, and 0.01 at 2.2 K, respectively. These values are of the same order as that of a commercially available bulk doped-SrTiO3 capacitance temperature sensor. These results reveal that the parallel capacitor with quantum paraelectric SrTiO3 film has potential for use in capacitance thermometers for monitoring cryogenic temperatures under high magnetic fields.