AN ELECTRON PARAMAGNETIC RESONANCE STUDY OF A CU2+-DOPED GUANIDINIUM ALUMINIUM SULPHATE HEXAHYDRATE SINGLE CRYSTAL IN THE 3.9-433 K TEMPERATURE RANGE - JAHN-TELLER EFFECT

摘要

Detailed X-band (about 9.5 GHz) EPR studies on a Cu2+-doped C(NH2)(3)Al(SO4)(2).6H(2)O single crystal have been carried out in the extended temperature range 3.9-433 K. Two magnetically inequivalent groups of Cu2+ complexes, each group consisting of three physically equivalent Cu2+ ions, were observed. The principal values of the g- and A-matrices characterizing the Cu2+ ion for one of these groups (site II) have been estimated at various temperatures, indicating a tetragonally elongated distortion of the octahedral local symmetry around the Cu2+ ions. The occurrences of static and dynamic Jahn-Teller effects below and above 423 K, respectively, have been observed. [References: 24]