Reciprocating thermal behavior in multichannel relaxation of cobalt(Ii) based single ion magnets

Abstract

A series of mononuclear Co(II) complexes showing slow magnetic relaxation is assessed from the point of view of relaxation mechanisms. In certain cases, the reciprocating thermal behavior is detected: On cooling, the slow relaxation time is prolonged until a certain limit and then, un-expectedly, is accelerated. The low-temperature magnetic data can be successfully fitted by assum-ing Raman and/or phonon bottleneck mechanisms of the slow magnetic relaxation for the high-frequency relaxation channel. An additional term with the negative temperature exponent is capa-ble of reproducing the whole experimental dataset.