The dominant mode of heat transport in the Earth controls the planet's internal dynamics and evolution. In this article, recent progress on in-situ high-pressure experiments of thermal transport properties of deep Earth materials is reviewed. The development of methods for measuring the thermal conductivity of minerals using diamond anvil cells has advanced our understanding of the thermal evolution of planetary interiors.

We report our recent progress in high-pressure magnetization and nuclear magnetic resonance (NMR) measurement techniques up to around 10 GPa. We developed two types of the opposed-type anvil cells for very precise magnetization measurement of quantum magnetism, and single-crystal NMR experiment for strongly correlated electron systems including superconductor. These have been established partly by using newly developed conical-shape gasket, giving rise to significantly larger sample volume. For practical NMR experiment, sealing method of liquids, electrodes, and optical fiber through a conical hole inside an anvil is also developed. To demonstrate those performance, high-pressure experiment of MnP is shown.

Temperature and pressure are essential parameters in the synthesis, evaluation, and application of functional materials. In this study, we fabricate a boron-doped diamond heater, thermometer, and measurement electrode on a diamond anvil. The proposed diamond anvil cell allows simultaneous control of temperature and pressure within the sample space and can be used to synthesize functional materials under extreme conditions. The various components of the boron-doped diamond can be used repeatedly until the anvil itself is broken. The developed system has been demonstrated via the high-pressure synthesis of BiS₂-based superconductors and the new compound Sn₃S₄. This technique shows promise for further exploration of superconductors to broaden the exploration space.

In this article, recent advances in the magnetic measurements under high pressures of above 10 GPa using superconducting quantum interference device (SQUID) were reviewed. SQUID is a magnetic device with high sensitivity, while it has a problem of drift in output voltage such that the offset mechanism should work to pick up a signal of targeted material. We review the experimental approaches using two types of apparatus; (1) sample transport method and AC magnetic field method by using a commercial SQUID magnetometer and (2) vibrating coil method by using a hand-made SQUID magnetometer.

This article reports technical developments of high-pressure dielectric measurement in the pressure range up to about 13 GPa. They had been developed to clarify how atomic or molecular dynamics changes under such extreme condition. Since the dielectric measurement is a relatively unused technique in high-pressure studies, a brief introduction of the definition and features of the physical properties is also described. Two example studies on ice using the developed cells shown in the last part will assist in the understanding of information obtained through the dielectric properties.