Magnetism of Cryostat Materials

Various modern substances are used in the construction of cryostats and low temperature experiments; but, unfortunately, there exist few systematic measurements of the susceptibility of these now common materials. Further, all previous similar surveys of susceptibility, while have been performed under very limited conditions[1,2,3]. Because of our lab’s frequent use of low frequency magnetic measurements at low temperatures, we desired a more comprehensive knowledge of these common materials’ magnetic properties. To fulfill our need, we conducted this experiment

The contributions to the magnetization measured in the samples include: permanent moments, core and Landau diamagnetism, Pauli paramagnetism, and isolated spin paramagnetism. In order to interpolate our data we fit each set of susceptibility data to a function of the form:

where Bj is the Brillouin function, and a, b, g, and M0 are fit parameters. We set j = 0.5 for most of our samples because the quality of the fit was not greatly affected by varying j. Fit parameter results are shown in the following table.


[1] G.L. Salinger, J.C. Wheatley, Rev. Sci. Instrum. 32, 872 (1961).

[2] J.M. Lockhart, R.L. Fagaly, L.W. Lombardo, B. Muhlfelder, Physica B 165 & 166, 147-148(1990).

[3] R.L. Commander, C.B.P. Finn, J.Phys. E 3, 78(1970).