INSTRUMENTATION

Electric transport measuring system (ETMS)

1. Electric transport measuring system (ETMS) is a system for multifunctional electric measurements of different samples under variable conditions. It includes:

  1. Cryogenic Micromanipulated Probe Station system (Janis Model: ST-500-2-(4CX-6PORTS). The cryostat ST-500-2 includes a 52 mm diameter electrically grounded gold-plated cooper sample holder. The sample chamber has 6 ports, which are connected to the following: four independent Coaxial Low Frequency single-tip probes with replaceable tips; one independent Kelvin probe (Besocke ltd.); and one fiber optic probe for sample spot-like illumination in the UV-visible range. All probes are mounted on micromanipulated X, Y, and Z translation stages, providing total travel: 50 mm (X), 40 mm (Y), and 10 mm (Z-vertical). Each stage is capable of an incremental translation of 12.5 microns with a typical sensitivity of 6 microns.

  2. Model 336 Automatic Temperature Controller (LakeShore) to measure and control the temperature. Control heaters and calibrated thermometers for active temperature control with a typical stability of 0.05K in the entire temperature range of 5-450 K.

  3. Turbo pumping station (HiCube 80 Eco Pfeiffer Vacuum GmbH) for vacuum.

  4. Antivibration set-up: Vibration isolation table, portable ultra-quiet air compressor, and a pump-line vibration isolator.

  5. Model ST-FHT high-efficiency multi-layer shielded liquid helium (or nitrogen) flexible transfer line with optimized valve and LHe and LN2 Dewars.

  6. Monoscope Color System with 3.4 μm optical resolution at a maximum magnification of 508X, at an 89 mm working distance. It includes a Monozoom Lens mounted on a vertical boom with vertical and horizontal adjustment: Travel stages with X=50 mm, Y= 50 mm, Z=32 mm travel; 1/3” Hitachi CCD camera: Fiber-optic light source; 18.5” LCD color monitor.

  7. To create vertical magnetic fields up to 2000 G, the probe station can use 6 ring permanent magnets with a special replaceable electrically isolated sample mount (25 mm diameter).

  8. Semiconductor Characterization system (Keithley Inc., model 4200-SCS) includes a computer with controlling software (KITE and other programs) and source-measure cards installed; 2 pulse measure units 4225-PMU with 4225-RPM amplifiers, 1 multi-frequency (10 kHz to 10 MHz) impedance measurement card 4200-CVU, and 4 source-measure units SMU-4200 with 4200-PA preamplifiers. Each source-measure card can be connected to any of 4 coaxial low-frequency single-tip probes of the probe station in order to measure the electric transport properties of the sample within the wide current and voltage ranges allowed by the 4200-SCS system.

Magnetic properties measurement system (MPMS-3)

MPMS-3 (LOT-Quantum Design company) represents the culmination of development and design in the world of SQUID Magnetometry. Providing users with the sensitivity of a SQUID (Superconducting Quantum Interference Device) magnetometer and the choice of multiple measurement modes, the MPMS 3 offers new levels of performance in magnetic research.
The MPMS 3 incorporates major advances in data acquisition, temperature (1.8 K ≤ T ≤ 400 K) control and magnetic field (-7T ≤ H ≤ +7 T) control with ≤10-8 emu sensitivity. The award-winning design of Quantum Design's MPMS 3 also provides expanded software functionality within its user-friendly MultiVu interface. Combining the highest level of system performance with the possibility of using all previously available MPMS measurement options, the Quantum Design MPMS 3 truly represents the next generation of advanced SQUID magnetometry.
MPMS 3 provides three possible measurement modes:
DC Scan Mode: Provides continual plotting and capture of raw data points at various fields and temperatures.
VSM Mode: Combines DC SQUID sensor with Vibrating Sample Magnetometer (VSM) technology, providing the ability to achieve < 10-8 emu sensitivity at zero magnetic field and <8*10-8 emu sensitivity at the full field of 7 tesla.
AC Susceptibility Mode: Using an oscillating magnetic field, this measurement uses the MPMS 3's SQUID and VSM linear motor to measure the AC Susceptibility of a sample.

The EverCool Dewar eliminates the need for liquid helium transfers and virtually eliminates all helium loss from magnetometer system. For the user, this integrated pulse-tube cryocooler dewar system can be considered cryogen free, as it not only recondenses the liquid helium directly within the EverCool Dewar but also accomplishes its initial cool-down directly from helium gas, thereby eliminating the need to use any liquid cryogens for the operation of the MPMS 3.

The Magneto-Optic Measurement option is a tool for investigations of photo-induced magnetization and related phenomena in samples. This option allows a sample to be illuminated by an external light source while conducting magnetic measurements. This option includes all the necessary parts and components to generate light of a certain wavelength and couple it in a Fiber Optic Sample Holder (FOSH) specifically designed for the MPMS3.

The Manual Insertion Utility Probe (MIUP) is a multifunction sample mounting platform, which is easily integrated into the base MPMS3. A micro-connector at the top of the sample rod connects 5 phosphor bronze wires to the sample mounting location. These 5 wires can be attached to the sample at the user’s discretion. The MIUP may be used for any application that necessitates up to 5 leads. Its design also allows users to perform a variety of resistivity measurements within the automated field and temperature environment that the MPMS 3 provides.