MAGNETIC STUDIES OF POLYMETALORGANOSILOXANES

Iron (3+) and cobalt (2+) polyorganosiloxanes were synthesized and cha racterized magnetically. The cobalt containing polymers were found to have a ferromagnetic ground state with a mean value of J of about 10K. The iron containing polymers demonstrated both ferromagnetic coupling with a mean J value ranging from 10 to 50K (depending on Fe concentra tion) and antiferromagnetic interaction with an exchange constant havi ng an absolute magnitude of about 10 times less. Several models were d eveloped to fit the experimental data. For both systems the best model found was the following: ion-ion coupling (5/2+5/2 for Fe and 3/2+3/2 for Co) arising from interactions within the polymeric chain, complic ated by inter-chain interactions which are positive and negative for C o and Fe, respectively. A molecular field approximation was used to ca lculate the contribution of this interaction.