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 dielectric sensitivity d ln(ε’)/dT≈2-8 K-1 is found to be 2-3 times higher in comparison to widely used glass-ceramic temperature 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 promising candidate for applications in capacitive temperature sensors for low temperature thermometry in high magnetic fields