Organic Polymer Ferromagnet

An organic ferromagnet was prepared by the polymerization of the paramagnetic stable biradical 1,4-bis(2,2,6,6-tetramethyl-4-oxy-5-piperyl-1-oxyl)-butadiene. The field dependence of the magnetization of samples prepared by photoinitiated polymerization was studied at 1.7, 4.2, 25 and 90K, with the results at the two higher temperature clearly showing ferromagnetic properties, albeit at only 0.1% of theoretical values. Curie temperature measurements with a vibrational magnetometer showed that some samples had a Curie temperature of 150-190 deg C. Variable results are due to the uncontrollable nature of the polymerization process. Further studies are in progress on fractions separated from the polymers by magnetic processes. 15 ref.--T.W.