Measurement principle

The electric polarization in pulsed high field is probed by pyroelectric current technique. In detail, gold electrodes (or silver pastes) are deposited on parallel surfaces of the sample and an electric field E is vertically applied to the golden surface to fully polarize the ferroelectric domains induced by a magnetic field. As the ferroelectric polarization P is generated in the sample, electric charges accumulate on the electrodes. And then the current I flows as labelled in Fig. 1 until the potential difference between the electrodes is equal to the one from the voltage source V_p. The pyroelectric current is detected by a voltage signal between the shunt resistor R_S (~10 kΩ). Usually, the R_S is used to be far smaller than the resistance of samples. The voltage across the R_s is collected by a measurement circuit, which is consisted of DC pre-amplifier, analog integrator, and analog-to-digital converters (ADC). Finally, the P is derived from integrating the pyroelectric current with the time.

Fig.1 Principle diagram of electric polarization measurement [JPSJ 76, 094709 (2007)]

Measurement Conditions

Magnetic field: 0-60 T

Temperature: 1.5-250 K (⁴He), 500 mK-4.2 K (³He‌)

Accuracy: ~0.1 μC/m²

Sample: Single crystal, Polycrystal

Size: S(area) < 7mm×7mm, d(thickness): 0.2-0.5 mm

Fig.2 Schematic installation of samples

Key Contact

Chengliang Lu

Email：cllu#hust.edu.cn (Please replace # with @)