Electrical and Magnetic Characterization
A Janis Cryogenic 10 T superconducting magnet with variable temperature insert operating from 1.25 to 325 K is present in Prof. Leighton’s lab. The system is equipped with calibrated high field thermometers, temperature controller, level meter, pumps, and electronics for DC (current source, voltage source, nanovoltmeter and source/measure unit) and AC (resistance bridge or lock-in) transport measurements. Using combined temperature control on the variable temperature insert and the sample stage heater temperature stability of order 1 mK can be achieved at 10 K. The system is capable of measuring resistivity, Hall effect, magnetoresistance and photoconductivity (via an optical fiber), and has a second probe which enables sample rotation in both planes. One probe is wired with sub-miniature stainless steel coaxial cables to enable low noise, high impedance measurements. A home-built oven insert provides access to temperatures up to 1000 K (in an O2 atmosphere if required) for high temperature transport measurements. In addition to this system we also have a high-throughput transport probe where resistivity measurements (using a second AC resistance bridge) can be made from 4.2 - 300 K by insertion in a helium dewar
Physical Property Measurement System: A cryogen-free Quantum Design PPMS (Physical Property Measurements System) with a temperature range between 1.7 K to 400 K and a 9 T magnet is present in Prof. Leighton’s lab. The system is equipped with a VSM (Vibrating Sample Magnetometry) option enabling high throughput magnetometry from 1.7 K to 1000 K. Additionally, Prof. Jalan’s lab has another fully operational cryogen-free Quantum Design PPMS Dynacool with a temperature range of 1.8 K to 400 K and a 9 T magnet. This system is also equipped with a thermal transport unit enabling thermal conductivity and Seebeck coefficient measurements from 1.8 K to 400 K.
SQUID Magnetometer: The Center has two Quantum Design XL7 SQUID systems, with 7T, 1.7 K field/temperature platforms. These systems are capable of measurements up to 800K (using an oven insert), a sample rotation (horizontal and vertical planes), AC susceptibility measurements, ultra-low-field operation, and a reciprocating sample option for higher throughput and sensitivity.
- High-Resolution Thin Film Diffractometer: This provides high-resolution, wide-angle diffraction measurements of thin films and superlattices, rocking curve and reflectivity measurements, in-plane diffraction, reciprocal space mapping and pole figure measurements.
- Wide Angle X-ray Diffractometers: There are four diffraction units. One is capable of diffraction between 4 K to 1400 K, a second has a high-intensity source and a 1-D line detector.
- Laue Diffractometer: The Laue diffractometer provides a high-throughput method of measuring crystal orientation.
- Microdiffractometer: This system has a sensitive 2D detector, useful for measurements of thin-film polycrystalline samples. Texture and single crystallinity can easily be determined.
- Low Angle Diffractometers and Grazing Incident Reflectometers: There are three units. One is equipped with 2D-area detector.
- Scanning Probe Microscope: Atomic force microscopy, scanning tunneling microscopy and near-field scanning optical microscopy. There are three Digital Instruments Nanoscope III units, one of which is capable of nanoindentation.
- Scanning Electron Microscopes: There are four scanning electron microscopes based on field-emission guns. Their capabilities include energy dispersive spectroscopy, crystallographic analysis, and texture mapping.
- Transmission Electron Microscopes: There are four transmission electron microscopes. These instruments are capable of electron energy loss spectroscopy and energy dispersive spectroscopy. The abberation-corrected FEI Titan 80-300 kV FEG TEM is capable of scanning TEM.
- Other Characterization Instruments: The Characterization Facility also has instruments for optical microscopy, Auger electron spectroscopy, secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, and other techniques.
- Photolithography: Available photolithographic patterning tools include masking capabilities for feature sizes down to 1.5 microns.
- Electron Beam Lithography: The Vistec EBPG 5000+ 100kV system is capable of linewidths less than 10 nm and large area patterning.
- Etching: Ion milling, deep trench etching, and several reactive ion etching tools are available.
- Deposition: The available instruments include several evaporators (thermal and electron beam for metals and alloys), sputtering systems (r.f. and d.c.), and tools for plasma-enhanced chemical vapor deposition, and atomic layer deposition.
- Other techniques: including wire bonding, rapid thermal annealing, profilometry, and ellipsometry.