Nanoscale Physics and Devices at Brown University
The main chamber of our high vacuum thin film deposition system features 5 water-cooled magnetron sputter guns, a 3cm Kaufman-type broad beam ion source, and a glow discharge plasma source. The vacuum is provided by a Cryo-Torr CT-8 cryopump, which typically provides pressure of 4X10-8 Torr.
An overview of the magneto-transport measurement facilities: the central equipment rack houses a current source, digital voltmeters, a frequency generator, two lock-in amplifiers, and power supplies for the probe station magnets; also pictured is the probe station (on the right) and the main control computer (on the left).
Our magnetic property measurement system features 2 SQUID (Superconducting Quantum Interference Device) detectors and a 5.5 Tesla superconducting electromagnet. The system is cooled by liquid helium and has a temperature range of 1.9K to 400K. The system is ideal for magnetic studies at low temperature and/or high field.
Our group developed a magnetic microscope, to be used for the imaging of dynamic magnetic fields. The prototype pictured here uses a conventional hard drive read head as a sensor. Future versions of the microscope will utilize our own magnetic tunnel junction based sensor.
For crystallographic characterization, we can use our own Phillips PW-1840 Diffractometer/PW-1829 X-Ray Generator system. The system features a scan angle of ~0 to 120° 2q. An excellent online guide to this system can be found here.
Our Hewlett Packard dynamic signal analyzer is used to study magnetic noise in magnetic tunnel junction based sensors. The magnetotransport parameters and the collection of data from the analyzer is controlled by computer via a custom LabVIEW user interface.
To improve the exchange bias and switching characteristics of the pinned layer of our magnetic tunnel junction structures, we anneal our samples in a magnetic field after depostion. Our annealing station, shown above, provides a uniaxial field of ~480 Oe.
Our sample preparation facilities include a mg scale, a diamond saw, and a ball mill (not pictured).