Emma Pugh

Automatic spark drill for high pressure experiments

A low cost automatic electric discharge spark drill has been developed for the preparation of gaskets for use in high pressure diamond anvil cells. The spark drill is capable of producing centered holes quickly in a wide range of metals. It makes use of a novel electrical feedback system and provides a method for accurate alignment of the cutting tool and gasket.

Novel metallic states at low temperatures

We present an overview of unconventional metallic states arising close to magnetic quantum critical points with a focus on d-electron systems. The applicability and potential breakdowns of traditional self-consistent field theories of such materials are discussed as well as related phenomena in other systems.

Electroplated mounting of diamond anvils for use in cryogenic systems

The mounting of diamonds using the electroplated deposition of copper was originally developed to hold diamonds in place during polishing. This article describes the extension and application of this method for the mounting of diamonds inside diamond anvil cells. The novel method described, unlike more traditional gluing or clamping methods, can withstand both continual thermal cycling and provide a small profile such that it can be used in miniature cells to permit ample space for fitting electrical feed throughs or external coils around the anvils. The method is developed such that it can be used to attach the diamond to nonmetallic backing plates such as sapphire. Details of precautions to reduce the production of eddy currents in the deposited copper when performing ac-susceptibility measurements are also described.

Note: Moissanite backing plates for use in diamond anvil high pressure cells

The use of moissanite (single crystal SiC) for backing plates within diamond anvil cells (DACs) has been developed. These have significant technical advantages in certain experiments. For example, moissanite is non-magnetic so is suitable for use in high magnetic fields and for magnetization experiments. Being translucent to light, including x-rays, means that openings are not required in the backing plate and as such has significant mechanical advantages and can provide enhanced scattering angles for x-ray diffraction experiments. The new backing plates have been successfully tested to over 25 GPa using diamond anvils with 0.5 mm culets.

Cryogenic loading of argon pressure medium in diamond anvil high pressure cells with in situ pressure determination

A versatile system for cryogenic loading of argon pressure medium into the sample space of a diamond anvil cell has been developed. The system has been designed such that, with suitable adaptors, a wide range of diamond anvil cell designs can be pressurized. The pressure in the cell can be monitored during pressurization using the ruby fluorescence method via optical fiber access into the loading chamber. This enables the precise and accurate setting of the loading pressure in the cell.