TESTING SUPERCONDUCTORS?

SOMETHING TO THINK ABOUT ...

A successful scientist knows how important it is to use the right tool for the job. Your instruments must perform well enough to make the measurements you need, but you can not afford to waste valuable research dollars (and the precious time it takes to raise them) buying instruments whose capabilities far exceed your requirements.

It is surprising, then, that many scientists believe they need a superconducting, SQUID-based magnetometer system to characterize the magnetic behavior of high Tc superconductors. There is no doubt that the SQUID systems are an important advance for measuring very weakly magnetic materials such as biological samples. However, using a SQUID system for characterizing high Tc material is simply OVERKILL. Overkill which is expensive - so expensive you will probably have to write a shared-instrument proposal to get the fund to buy one. Overkill with a delivery time measured in years, after you raise the necessary funds.

At Abbess Instruments we believe we have the right tool for this job: the Abbess Instruments Zeamer Faraday Susceptibility System. We have combined our expertise in cryogenics and engineering with proven microbalance and electromagnet technology to build a variable temperature force magnetometer system with all the sensitivity you need (and more). Even with only 10 mg of sample, our instruments can detect a change in mass susceptibility of less than 2 x 10-11 emu/g. For a 1-2-3 compound, the full Messier effect corresponds to about 10-2 emu/g, i.e. our instrument can detect superconductivity in only a few parts per million of the sample. Of course, it is also now believed that the normal state magnetic properties of these materials are an important measure of the local environment of the copper ions and the relative occupancies of oxygen sites. Measuring the normal state susceptibility is also well within the capabilities of our instrument. With our CTC-1 cryostat, you only need liquid Helium when you want to work below 77K, not all the time. (For sample temperatures above room temperature, you do not need cryogen's at all!) And our systems work to 5000C+, standard.

At Abbess Instruments, we know that scientists like to do things their own way, and may already have some of the needed equipment. So we give you choices. You can provide your own thermometry and temperature controllers, or we can select and provide them for you. You may even already have a suitable electromagnet and/or a microbalance. You probably have a lab full of computers and your favorite software for measurement and control or we can provide what you need. We are here to help you get a working system, but we will not baby you or force you to buy more than you want.

So now you have a choice. You can wait in line to spend money you can not afford, to buy capabilities you do not need. Or, you can come to us.

Cava et al. (1987) Nature 329, 423-425