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Magnetic and Physical Properties Measurement Facility | ||
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Director Professor John Ketterson, Physics & Astronomy Tele: (847) 491-5468 Email: j-ketterson@northwestern.edu |
Location Technological Institute FB24 2145 Sheridan Road Evanston, IL 60208 |
Research Associate Oleksandr Chernyashevskyy, PhD Tele: (847) 491-4212 Email: o-chernyashevskyy@northwestern.edu |
Function The Electronics Shop is your high-tech resource for solving electronic, instrumentation, control, and data acquisition problems. We can repair just about anything you can plug into an electrical outlet. We troubleshoot, repair, adjust, modify, calibrate, and develop: electronics, computers, and computer-controlled scientific and industrial instruments. We can assist researchers with circuit design. We maintain a stock of electronics components, batteries, computer parts, cables, etc. We maintain electronic testing equipment for standard electronics as well as test software and hardware test systems for computer-controlled instruments. We can even serve as a recycling / surplus collection point for departmental electronics and computers. Measurement Services This non-profit facility maintains various contemporary scientific instruments capable of highly accurate measurements. These systems are designed to be as flexible as possible, and to allow measurements to be performed over a wide range of magnetic field, temperature, and (where applicable) probe frequency. Measurements that are routinely performed include magnetization and magnetic susceptibility, acoustic propagation, microwave absorption, electrical and thermal transport, thermoelectric measurements, heat capacity, and low-noise I-V curve measurements. We are experts in the improvement of customer instrument performance (reduction of noise and interference, increase in signal to noise ratio, etc). We can design and manufacture a variety of interfaces and preamplifiers for your systems. Repair Services We have a great deal of experience in the repair, adjustment, and servicing of scientific instruments, including aging systems that companies no longer support. When laboratory equipment in your department or company is not functioning, our job is to make it see the error of its ways. You can't find schematics or service manuals for faulty devices and instruments? Contact our office! Below is a partial list of the aged and modern equipment we work on: Various programmable logic controllers, computer control consoles Magnetic Properties Measurement System (MPMS - Quantum Design) Physical Properties Measurement System (PPMS - Quantum Design) Nuclear Magnetic Resonance Spectrometer (Varian) Vacuum equipment (Turbo-molecular vacuum pump, leak detectors, gages, etc) Oscilloscopes, power supplies, meters, recorders, etc Old and modern computer-hardware-related problems (controllers, LCD monitors, power supplies, tape and floppy drives) What we often find is, if Oleksandr can't fix it then it can't be fixed. Modification Services Is the signal-to-noise ratio of your instrument poorer than necessary? We have experience in reducing the noise of brand new and aged instruments. For example, we have improved the signal-to-noise ratio of a Quantum Design PPMS for studying Josephson Junction current-voltage characteristics. Need to modify instruments and systems for better compliance to customer research needs? If you need a custom circuit or option, we can design one for you. Don't waste time trying to do it yourself. Let our professional staff empower your research or instruction with custom circuitry. We may already have the design you need. Get your specifications together and come to Tech FB24. Previous designs include: PPMS Helium-3 Insert (0.6K) Low noise computer interfacing Switch-boxes (JPG) Battery powered low noise computer controlled ramp generators and preamplifiers Various sensors Low-level opto insulated amplifiers Low voltage DC power supplies High voltage switching DC power supplies Precision current source for electrochemistry Light sensors Motor controllers Equipment Our equipment includes cryostats, magnets, magnetometers, a nanovoltmeter, constant-current sources, and constant-voltage sources. The magnetometers include a computer-controlled Quantum Design (http://www.qdusa.com) Magnetometer (MPMS5) that permits SQUID magnetic-moment sensitivity (and a user probe for transport measurements), a LAKESHORE AC susceptometer for measuring both real and imaginary components of susceptibility, and a quick-turnaround AC bridge susceptometer. The MPMS provides the exceptional sensitivity of a SQUID-based magnetometer in a fully automated, analytical instrument. It provides a much needed solution for a unique class of magnetic measurements, meeting the needs of research in key areas such as high-temperature superconductivity, biochemistry, and magnetic recording media. This system was upgraded in 2004 by the addition of a horizontal rotator option and an "oven" insert for high-temperature measurements. This instrument can measure DC magnetic susceptibility and magnetic moments on samples as small as a few mg.Ease Of Use The hallmarks of our instruments are automation and ease of use. We can quickly and easily configure them to perform different types of measurements. In a matter of minutes we can install a measurement application, set up an automated sequence, and start collecting meaningful data. And, our equipment is designed to run 24 hours a day, 7 days a week. We know your time is valuable, so we have laboratory automation on a new level. While the PPMS or MPMS runs your measurements, you can be analyzing data from previous measurements, planning your next experiment, and creating new materials. The MPMS and PPMS work like dedicated systems, but their tremendous flexibility lets you perform different types of measurements. Plus, we can easily integrate a user's unique experiment with our measurement systems. Samples can be easily prepared from a variety of materials. The exceptional dynamic range of our devices allows us to accommodate samples in many forms, from single crystals to bulk solids, films and powders. MPMS and PPMS Applications Physics Condensed matter scientists can use the systems for low-temperature investigations in high magnetic fields. The exceptional dynamic range of the SQUID amplifier allows the MPMS to accommodate samples in many forms, from single crystals to bulk solids and powders. These features, taken together, create a powerful tool for studying material properties and transmaterial phenomena. These tools are commonly used to study artificially layered structures, dichalkogenides, fullerenes, paramagnetic films, spin glass materials, the Hall Effect, antiferromagnetism, heavy fermions, high and low temperature superconductivity, magnetic hysteresis, and the Meissner effect - with more to come as areas of scientific investigation continue to expand. Materials Science Characterization of the magnetic properties of new materials is central to materials science. Not surprisingly, the MPMS and PPMS are major tools in the effort to understand and optimize the synthesis processes of materials such as amorphous alloys, intermetallic compounds, magneto-optic materials, mesostructures, multilayered materials, nanocomposite materials, rare earth compounds, superconductors, superlattices, thin films, transition metal oxides and weakly magnetic materials. Chemistry Magnetochemistry focuses on the interrelationship between magnetic fields and atomic and molecular structures. In organic chemistry, analysis of magnetic susceptibility, paramagnetic resonance and other properties aids in evaluating the exchange energies and valence of electrons in compounds, such as catalysts and highly complex compounds. The MPMS can be used to examine the properties of materials being synthesized, such as magnetic thin films, superlattices, magneto-optic materials, ceramics, and metaloproteins. The broad temperature range of the MPMS and PPMS, including its ability to work well above and below room temperature, allows researchers to extend their studies into regimes outside the capabilities of other instruments. Biology Growing fields of inquiry include bioelectromagnetism - which investigates the effect of electromagnetic energy on biological systems - and biomagnetism - which analyzes the magnetic fields produced by living organisms themselves. Fields in the 10-14 to 10-9 Tesla range result from ion currents in muscles, nerves, and organs such as the brain, lungs and liver and from concentrations of iron in animal tissue and chlorophyll. For example, magnetotactic bacteria will swim northward in induced magnetic fields as small as 0.1 Gauss (in comparison, the earth's field at the surface is 0.5 Gauss). Their "internal compass" is a minute amount of iron organized into crystals of magnetite. There is also research into the possibility that certain viruses may have magnetic preferences. The study of magnetism plays a role in the design of pharmaceuticals and the understanding of fundamental processes like photosynthesis. Using the MPMS to increase understanding of phenomena such as these may lead to the development of enhanced diagnostics and therapeutic techniques. Geology Analyzing rock samples provides important information about planet Earth - from studying its early history to the dynamic internal changes with vulcanism and plate tectonics. For example, inspecting specimens from ancient sea-bed lava flows provides data on periodic reversals in the Earth's magnetic field. Geophysical studies of anisotropy, susceptibility, remanence, coercitivity and transformation in samples can require very high temperatures. The MPMS can be tailored to this application by adding the Sample Space Oven, which extends its temperature capabilities to 700 K. Samples with very high inherent magnetic moments can be measured using the Extended Dynamic Range option. Electronics Deeper understanding of the magnetic and electrical properties of materials is crucial to the electronics industry. The focus is on miniaturization, speed and lower heat dissipations - packing devices as closely as possible to shorten communication distances and boost performance. Studies of LTS and HTS superconductors and semiconductor materials such as gallium arsenide are of increasing importance. Magneto-optics, dealing with the influence of magnetic fields on a material's absorption, emission, or reflection of light, is also an important new application area. Fees The fee for services provided is $65/hr for commercial use, $45/hr for University and government-funded research. Free estimations. Job sheets or letters must be filled out for all electronics shop jobs. They must include the name of the person who is initiating the job, the research advisor and/or person who is paying for the job, and a job name. If the job is a modification or addition to a pre-existing item of equipment, please state the name of the equipment. List of selected publications Our Shop has provided technical support (including the design and fabrication of special electronics) for the research presented in the following publications: I. P. Nevirkovets, O. Chernyashevskyy, J. B. Ketterson, and E.Goldobin, "Fabrication and Characterization of Multi-Terminal Superconductor-Insulator-Normal Metal-Insulator-Superconductor Josephson Devices", J. Appl. Phys. 97, 123903-12908 (2005) I. P. Nevirkovets, O. Chernyashevskyy, and J. B. Ketterson, "Direct Study of the Proximity Effect in the Normal Layer Inside of the Stacked SINIS Device", Phys. Rev. Lett. 95, 247008 (2005) I. P. Nevirkovets, O. Chernyashevskyy, and J. B. Ketterson, "Characteristics of Zr-Based Single- and Multiple-Barrier Superconducting Tunnel Junctions", Appl. Phys. Lett. 88, 21504 (2006) I. P. Nevirkovets, O. Chernyashevskyy, and J. B. Ketterson, "Absence of Enhanced Superconductivity in Double-Barrier Superconducting Tunnel Junctions: Measurements of Lateral Electric Transport in the Middle Normal-Metal Layer", Phys. Rev. B 73 224521 (2006) I. P. Nevirkovets, S. E. Shafranjuk, O. Chernyashevskyy, and J. B. Ketterson, "Enhancement of the Supercurrent at a Finite Voltage in a Sandwich-Type Ballistic SINIS Junction", Phys. Rev. Lett. 98, 127002 (2007) | ||
