A sensitive capacitance thermometer at low temperature for use in magnetic fields up to 20 T

Abstract

We have established the magnetic-field independence up to 20 T of a capacitance thermometer based on the incommensurate crystal (Pb0.45Sn0.55S)2P2Se6 in the temperature range from 25 mK to 0.5 K. The sensitivity of the thermometer, d ln C/d ln T, is 5×10-3 at low temperatures and is about an order of magnitude larger than for any other previously reported capacitance thermometer. The most sensitive temperature range of the thermometer can be tuned by varying the measuring ac frequency and voltage. The reproducibility of the thermometer upon cycling below 1 K is better than 1 mK. © 1996 American Institute of Physics.