Resistance thermometry in magnetic fields 1. Thermistors and platinum thermometers at 77 K

✍ Scribed by J.E. Vevai; D.G. Elliot; W.I. Honeywell

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 313 KB
• Volume: 12
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(72)90084-7

✦ Synopsis

The effects of static magnetic field up to 16 kG on seven midget disc thermistors and three miniature platinum resistance thermometers were measured at 77 K. Corrections for the magnetoresistance of the electrical leads and solder junctions were made from data taken on a copper wire coil. A virtual temperature rise of the order of millikelvins occurs for both temperature sensors," the lead wire correction is less than a few microkelvins. The thermistors have larger magnetoresistance effects than similar types recommended for use at lower temperatures. A figure of merit comparison suggests that they are slightly less desirable than platinum thermometers in magnetic fields at liquid nitrogen temperatures.

Resistance thermometry in magnetic fields 1. Thermistors and platinum thermometers at 77 K

J. E. Vevai, D. G. Elliot, and W. I. Honeywell

In order to make accurate measurements of temperature with electrical resistance thermometers in the presence of strong magnetic fields, the effect of the magnetic field on the temperature sensor must be known. Magnetoresistance effects have been reported on carbon resistors, 1-5 germanium resistors, 2,6-8 and GaAs diodes 9 over the temperature ranges from 2 K to 65 K. The effects become larger as the temperature to be measured decreases. In fact, at low enough temperatures (< 4 K) and high enough fields (> 100 kG), it is not uncommon to find the perturbation on the resistance becoming comparable to the resistance itself and sometimes even to exceeding it.