Ferromagnetic Films Derived from Laboratory Prepared AromaticPolyimide Film PMDA/ODA by Heat Treatment

摘要

A Kapton-type aromatic polyimide film (PMDA/ODA) was prepared by thermal imidization. The change of magnetization of the filmrnby heat treatment at temperatures between 500 – 530rnwas investigated, and the results were compared with those obtained previously forrncommercially available polyimide film Kapton. The prepared and heat-treated films were found to contain no metallic elements.rnFerromagnetism was observed clearly for the 520rn-treated film even at 300K, as had been observed for the 520 -treated Kapton,. Thernferromagnetism should be caused by a long-range magnetic ordering of unpaired electrons located on slightly decomposed imide moleculesrnwith defects or on intermediates with free radicals formed by pyrolysis.