Hi all, I am learning about magnetometers. Esp. those based on the Overhauser effect (https://en.wikipedia.org/wiki/Nuclear_Overhauser_effect). As I understand, they embed a free radical fluid that contains free electrons that gets polarized through a RF field. Do you have any idea what free radical liquid is used in commercial models ? I do not see any toxicity warning in datasheet I browsed so far (http://www.gemsys.ca/products/rugged-overhauser-magnetometer/) Thanks a lot for your ideas !