Method for measuring specific heats in intense magnetic fields at low temperatures using capacitance thermometry

Abstract

A drift method is described for measuring specific heats in intense magnetic fields at low temperatures. Capacitance thermometry is used, and an automated data‐collection system utilizes the imbalance of a transformer‐ratio‐arm bridge to process the capacitance data. The zero‐field specific heat must be known, and measurement of the in situ drift in zero‐field calibrates the thermal link. Additional calibration of the link is required if the link’s magnetothermal conductivity effects are significant, and a specific example of a copper‐wire link is presented. The method resolves complex structure in the specific heat near a steep λ‐type anomaly, as illustrated by measurements on a chromite spinel at 7.5 T. The uncertainty in the method is estimated to be ≂±7%.