Miyake Atsushi, Mitamura Hiroyuki, Kawachi Shiro, Kimura Kenta, Kimura Tsuyoshi, Kihara Takumi, Tachibana Makoto, Tokunaga Masashi
The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Department of Advanced Materials Science, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
Rev Sci Instrum. 2020 Oct 1;91(10):105103. doi: 10.1063/5.0010753.
We report on the development of a capacitance measuring system that allows measurements of capacitance in pulsed magnetic fields up to 61 T. By using this system, magnetic-field responses of various physical quantities, such as magnetostriction, magnetic-field-induced change in complex dielectric constant, and magneto-caloric effect, can be investigated in pulsed-magnetic-field conditions. Here, we examine the validity of our system for investigations of these magnetic-field-induced phenomena in pulse magnets. For the magnetostriction measurement, magnetostriction of a specimen can be measured through a change in the capacitance between two aligned electrodes glued on the specimen and a dilatometer. We demonstrate a precise detection of valley polarization in semimetallic bismuth through a magnetostriction signal with a resolution better than 10 of the relative length change. For the magnetic-field-induced change in complex dielectric constant, we successfully observed clear dielectric anomalies accompanied by magnetic/magnetoelectric phase transitions in multiferroic Pb(TiO)Cu(PO). For the measurement of magneto-caloric effect, a magnetic-field-induced change in sample temperature was verified for GdGaO with a capacitance thermometer made of a non-magnetic ferroelectric compound KTaNbO (x = 0.02) whose capacitance is nearly field-independent. These results show that our capacitance measuring system is a promising tool to study various magnetic-field-induced phenomena, which have been difficult to detect in pulsed magnetic fields.
