Paramagnetic Anisotropy, Electronic Structure, and Ferromagnetism in SpinSthinsp;equals;thinsp;32Manganese(II) Phthalocyanine

摘要

Measurements are reported of magnetization and the average magnetic susceptibility of manganese (II) phthalocyanine in the range 1.7ndash;300deg;K, which confirm that the Mn(II) atom is in anSthinsp;equals;thinsp;3thinsp;sol;thinsp;2spin state, and that weak ferromagnetic interactions are present in the crystal, presumably between adjacent molecules. Single crystals of MnPc are moderately anisotropic; the principal magnetic momentmgr;Verbar;thinsp;equals;thinsp;4.0 mgr;Bremains constant between 80ndash;300deg;K whilemgr;perp;increases from 4.4mgr;B(300deg;K) to 5.0mgr;B(90deg;K). This magnetic anisotropy is consistent with a4A2gground state into which the excited term4Egis mixed by spinndash;orbit coupling. Possible pathways for superexchange are considered.