Magneto-electric Effect and Dielectric Susceptibility Measurement Technique at Very Low Temperature

We report the design and operation of a new device for measuring the magneto-electric effects, dielectric susceptibility, and electrical resistance of materials at very low temperatures (below 10 mK). The unique feature of the device is the immersion of the sample in liquid \(^{3}\hbox {He}\) which is cooled with a large (\(25\hbox { m}^{2})\) surface area sintered silver heat exchanger connected to the nuclear stage of a demagnetization refrigerator. In addition to a DC applied magnetic field (up to 16 T), an AC magnetic field is provided by a Helmholtz coil located outside the sample. With this design the magnetic field-dependent electric susceptibilities, and the DC and AC resistance can be measured simultaneously. The details and performance of the device are discussed, and measurements on interesting new materials such as quantum organic magnets are presented.