Shinya Uji

High magnetic field corrections to resistance thermometers for low temperature calorimetry

We present a general analytical method of correcting for magnetic-field-induced changes in both the apparent temperature and the sensitivity of resistive thermometers at dilution refrigerator temperatures. With this method, we are able to reduce magnetic field induced errors in temperature to a level limited only by our ability to regulate the temperature in the absence of a magnetic field. We illustrate the application of our method to two resistive sensors in magnetic fields up to 18 T: a custom-made AuxGe1−x thin film sensor used in calorimetry and a commercially available ruthenium–oxide thick film resistor used in thermometry.

Irreversibility line and lock-in transition in Tl2Ba2CuO6 single crystals

Abstract We investigated the irreversibility lines (Hirr) and their correlation with lock-in transition on over-doped Tl2Ba2CuO2 single crystals using magneto-resistive measurement results. The lock-in transition is observed only above the irreversibility line Hirr⊥(t) for magnetic field H‖ c-axis, where t=T/Tc is the reduced temperature.