Quantum Design PPMS with Evercool Dewar
About the Instrument:
“The PPMS is an entire lab combined into one instrument,” says Jeff. It measures specific heat, thermal conductivity, electrical conductivity, magneto-resistance, Hall effect, thermo-electric power, magneto-thermo power. There’s also a vibrating sample magnetometer which allows you to measure magnetic properties. It offers a range of temperatures from 1.5 K to 800 K and will measure to a magnetic field of up to 9 Tesla. Using a high pressure insert, it will go up to 14,000 times atmospheric pressure. “It means we can study properties as a function of temperature, pressure and magnetic field all rolled into one,” says Jeff.
“The PPMS is a very versatile system that greatly expands our capability. In many cases to do this sort of thing we’ve had to go overseas or have collaborators offshore but now we have the equipment and the relationships to do it all here in New Zealand.” The PPMS opens up a number of new measurements and increases the sensitivity of those that were available. It saves time and money on travel and it’s all computer controlled. “It’s very straight forward to set up a programmed schedule for a set of samples and to run through those in automatic fashion,” says Jeff. This means that the machine can stay busy when the researchers have gone home. “On a Friday evening,” he says, “you can set it up to run for 24 hours so typically it’s used six days a week.” The PPMS is helping researchers produce more papers of a better quality. It may also help in the commercialisation of research. CallaghanInnovation researcher, Grant Williams, for example, is developing sensor technologies, which he is looking to commercialise. PPMS measurements will be essential for this development.
Jeff’s group is already internationally renowned for their work with superconductors and have close collaborators at Cambridge University and other top international research organisations. “It’s all very well having good people,” Jeff says “but unless you have the equipment to go with it, you can’t achieve a great deal.” Instruments such as the PPMS and SQUID Magnetometer are common in labs overseas. “You can go to a Japanese laboratory,” Jeff says “and there’ll be three SQUIDs sitting in the one laboratory plus a couple that are getting a bit old sitting out in the corridor.” In itself, the PPMS won’t draw hoards of overseas visitors to the lab. It’s more about bringing research capability up to an international standard. “There are a lot of people in New Zealand who are keen to do these kinds of measurements,” Jeff says. He believes that providing the infrastructure with ‘no strings attached’ encourages openness and collaboration. He has also found that the new equipment is providing a much needed boost in confidence and motivation to NZ researchers.
Story by Ruth Beran Hysteresis Many materials have memory. If a rubber band is stretched, for example, and then let go, it will be slightly larger than before it was stretched. This is called elastic hysteresis. Similarly, materials like iron can be magnetised, and will remain magnetised indefinitely, until demagnetised by heat or a magnetic […]