A compact bellows-driven diamond anvil cell for high-pressure, low-temperature transport measurements
The Diacell® ChicagoDAC was developed in full collaboration with the group of Prof. Rosenbaum – then at the University of Chicago; now at Caltech. The principle of operation of the cell is described in detail on Feng, et al. Rev. Sci. Instr. 85, 033901 (2014).
The ChicagoDAC is an efficient bellows-controlled diamond anvil cell that is optimized for use in the Quantum Design PPMS platform, but it can be equally adapted to fit inside the bores of high-field superconducting magnets in helium-4 cryostats (with or without liquid helium), helium-3 cryostats, and dilution refrigerators.
The diamond anvil cell is non-magnetic and provides in situ pressure tuning and measurement by means of a helium-filled bellows actuator and fiber-coupled ruby fluorescence spectroscopy, respectively. An insert is available to accommodate the gas coupling to the bellows and the necessary optics for ruby fluorescence manometry. For the latter, in particular, a single multimode optical fiber carrying both the incident light and the emitted spectrum coupled to a pair of plano-convex lenses provide a wide-aperture coupling between the fiber and the pressure chamber. This efficient coupling allows the cell pressure to be measured with incident light power in the tens or hundreds of μW range, minimizing any local heating that might occur during the measurement.
As such, the ChicagoDAC provides an opportunity to probe a variety of phenomena continuously and with high resolution in the three-dimensional high-magnetic-field, high-pressure and low-temperature parameter space.
One particular exciting application is having the ChicagoDAC equipped with our new development of patterned diamond anvils to enable seamless transport measurements at the extreme conditions. The patterned diamond anvils have electrically conducting tracks deposited on culet and pavilion, which enables making contacts to the sample much easier.
Similarly, susceptibility measurements are equally possible and the paper by Feng et al. referred above gives details on how to pursue that.
Finally, because of suitable optics already present in the ChigagoDAC’s insert, other spectroscopic measurements such as fluorescence and inelastic scattering (Raman) are also feasible with the same set-up. An optical fibre is supplied with the insert to enable the coupling to an optical system via a SMA connector. A gas relief valve is supplied with the insert and is fitted at room temperature.
A video showing the Diacell® ChicagoDAC (including the insert and patterned diamond anvil) is available on our YouTube channel.