Resonance in the Nonlinear Susceptibilities of Co3BTCA2(H2O)4, a Molecular-Based Magnet

The linear and nonlinear magnetic responses of the molecular-based magnet Co3BTCA2(H2O)4 have been studied as a function of frequency and temperature. The out-of-phase component of the linear susceptibility and the nonlinear susceptibilities all show maxima at the critical temperature of 23 K while displaying a novel resonance in their frequency dependence. The existence of the resonance in the out-of-phase component demonstrates the absence of dynamic scaling in this magnetic system.