Equipment

This is the first of two PPMS systems in the facility. It provides magnetic field up to 9 T and temperatures from 1.7 K to 400 K. Users are able to perform DC magnetic moment, AC magnetic susceptibility, 2- and 4-wire magnetoresistance, photoconductivity, and Hall effect.

This system benefits from the PPMS EverCool-II™ dewar, which is the second generation of low-loss dewars with integrated Helium liquefier for the PPMS system from Quantum Design. It allows the continuous operation of the PPMS System without the supply with liquid Helium. The system is cryogen free for the user, and can hold temperatures below 2 K indefinitely.

This is second of two PPMS systems in the facility. It provides magnetic field up to 9 T and temperatures from 1.7 K to 400 K. Users are able to perform 2- and 4-wire magnetoresistance, thermal conductivity, heat capacity, Seebeck coefficient, and Hall effect measurements. The system is equipped with a turbo pump for the sample chamber.

Quantum Design’s MPMS-XL provides sensitive SQUID (Superconducting QUantum Interference Device) magnetometry capabilities using Quantum Design’s Reciprocating Sample Option (RSO). In practice, we observe a noise floor of <10^-8 emu for DC moment measurements. The system provides magnetic fields up to 7 Tesla and temperatures nominally between 2 K and 400 K. The MPMS has a fiber insert that permits studies of optically pumped magnetization, and an oven option that allows measurements up to 800 K when special needs arise.

MPMS XL Features

• Cryogen Free with EverCool^®
• SQUID Sensitivity
• Multiple Measurement Modes
  (Including Traditional MPMS DC Scan)

• Temperature Range: 1.8 – 400K
• 7 Tesla Magnet

The TriVista system is a triple spectrometer that has multiple input and detection ports that we can configure to provide Raman scattering down to 5 cm^-1, photoluminescence excitation/emission spectral mapping, absorption, as well as spatial imaging of Raman scattering or photoluminescence with an infinitely tunable (in width and center wavelength) bandpass filter from 350 nm to 1000 nm. For Raman scattering, the system can operate in either additive mode for high resolution experiments or in subtractive mode for extreme stray light rejection. The system has both Si and InGaAs detectors, providing detection bandwidth from 350 nm to 1.7 microns. Light sources include a Xenon lamp (from which any spectral range can be selected without altering the illumination profile) and a laser at 532 nm. We are able to measure samples on solid substrates and liquids within cuvettes.

Instrumentation

• Princeton Instruments Tri-Vista 555 spectrometer (9 gratings)
• Princeton Instruments PIXIS-256E Si 2D array detector
• Princeton Instruments OMA-V InGaAs linear array detector
• Custom Optical Systems for Absorbance, Photoluminescence and Raman Scattering.