NEW DIELECTRIC MATERIAL FOR LOW-TEMPERATURE THERMOMETRY IN HIGH MAGNETIC-FIELDS

Dielectric experiments on the incommensurate solid solution (Pb0.45Sn0 .55)2P2Se6 for T = 1.2-200 K reveal a strong temperature dependence of the real part of the dielectric constant for T < 45 K. The relative d ielectric sensitivity d ln(epsilon')/dT almost-equal-to 2-8 K-1 is fou nd to be 2-3 times higher in comparison to widely used glass-ceramic t emperature sensors. Moreover, the dielectric constant has a very good time stability and is insensitive to magnetic fields up to 20 T (dT/dB < 10(-4) K/T). These characteristics make this material a very promis ing candidate for applications in capacitive temperature sensors for l ow temperature thermometry in high magnetic fields.