In this article, high pressure medium, Daphne7474 and Daphne7575 which solidify around 4 GPa at 25℃ is presented. Most of the physical high pressure parameters of Daphne7575 are slightly superior to those of Daphne7474. However, probably the great benefit with Daphne 7575 is that this new material would more easily be spread to because of the (expected) less strict international trade regulations for this material.
In this article, recent advances in cubic anvil cell (CAC) using an integrated-fin gasket technique, which extends the pressure range up to 16 GPa, were reviewed. We demonstrate that the high quality 10 GPa-class pressure using CAC allows us to extract the intrinsic properties, and to explore novel phenomena in strongly correlated electron systems.
In this article, we have reviewed our recent experimental study of quantum criticality of Mott metal-insulator transition in organic materials. Resistivity measurements of three organic systems with different ground states were performed under continuously controlled pressure by using helium as a pressure medium. The resistivity obeyed the material-independent quantum-critical scaling relation bifurcating into a Fermi liquid or Mott insulator, irrespective of the ground states.
In this article, the characteristics of the indenter-type high-pressure cell which was developed in our laboratory and the physical properties of Daphne oil 7474 were described. Some phase transitions which can be observed due to the improvement of hydrostaticity were reviewed. In these systems, the lack of hydrostaticity often caused the broadening and the disappearance of the phase transition.
In this article, we present an experimental setup for high-pressure resistivity measurements up to 3.2 GPa and its application to EuFe2As2, a mother compound of iron-based superconductors. Hydrostatic and nonhydrostatic pressures are produced by Daphne 7474 and Stycast 1266 pressure transmitting media, respectively, using a piston-cylinder-type NiCrAl/CuBe high-pressure apparatus. It is found that, in EuFe2As2, application of hydrostatic pressure is essential for the appearance of bulk superconductivity at Tc～30 K in the limited range of 2.5-3.0 GPa. Quality of pressure generated via Daphne 7373 and 7474 are also evaluated by use of two Manganin wires arranged parallel and vertical to the load axis.
This article reviews required properties for cylinder material for piston-cylinder high pressure apparatuses, and show that zirconium-based bulk metallic glass (Zr-BMG) has outstanding properties as a cylinder material. The piston-cylinder made of the Zr-BMG cylinder sustains pressures up to ～2 GPa, which is estimated by the pressure dependence of superconducting temperature of lead. The Zr-BMG cylinder is particularly useful for neutron scattering experiments owing to its remarkable transparency for neutron, and also potentially useful for SQUID measurements owing to its relatively low magnetic susceptibility.
Effects of hydrostatic pressure on a thin film of helimagnet MnSi were reviewed. The MnSi film exhibits similar non-Fermi liquid (NFL) behavior near the pressure-induced quantum critical point to that observed in bulk MnSi, although its temperature range is extended to higher temperature side compared with the bulk sample. Since the NFL behavior of MnSi is related with presence of “Skyrmion”, the extended NFL region observed in the thin film may come from stabilization of the Skyrmions due to uniaxial anisotropy. Furthermore, we discussed a general role of hydrostatic pressure in a thin-film sample grown by molecular beam epitaxy.