Contact: ALBIN de MUER (GRENOBLE)
The specific heat measurement requires to detect a change in sample temperature upon heating it.
The sample is glued on a resistive chip used as a sample holder, a thermometer and a heater. Wires with specific material, length and diameter are chosen to hang the setup, to measure the chip resistance and to provide the suitable thermal conductance depending the heat capacity of the sample. Extremities of wires are thermally connected to a thermal bath stabilized in temperature owing to a reference temperature and magnetic field calibrated thermometer.
A square shape current signal is injected in the chip and the large induced temperature relaxations, as large as 100% of the bath temperature, are measured with accuracy and a high sample rate (around 1000 points over a time range from 1 to 100 s).
Specific heat is then computed on the whole temperature range relaxation, providing an accurate and fast measurement suitable for high magnetic field measurement.
Ideal dimensions for the sample consist of thin platelets (few hundred µm) with an area close to mm². Good internal thermal conductivity is required for quality of the measurement. Field orientation may be chosen, in-plane or perpendicular the platelet.
Above we show specific heat measurements in the heavy fermion compound CePt2In7. At the magnetic transition an anomaly is observed in the specific heat (left). This anomaly is tracked up to high magnetic fields in order to construct the phase diagram of this material (right). Check here for more info on theses results.
| Bmax | Temperature range | Duration per field |
|---|---|---|
| 36 T | 0.5 K - 4 K | 1 - 3 h |
| 36 T | 4 K - 40 K | 2 - 4 h |