Study of Low Temperature Magnetic Properties of a Single Chain Magnet With Alternate Isotropic and Non-Collinear Anisotropic Units

摘要

Here we study thermodynamic properties of an important class of single-chainmagnets (SCMs), where alternate units are isotropic and anisotropic withanisotropy axes being non-collinear. This class of SCMs shows slow relaxationat low temperatures which results from the interplay of two differentrelaxation mechanisms, namely dynamical and thermal. Here anisotropy is assumedto be large and negative, as a result, anisotropic units behave like cantedspins at low temperatures; but even then simple Ising-type model does notcapture the essential physics of the system due to quantum mechanical nature ofthe isotropic units. We here show how statistical behavior of this class ofSCMs can be studied using a transfer matrix (TM) method. We also, for the firsttime, discuss in detail how weak inter-chain interactions can be treated by aTM method. The finite size effect is also discussed which becomes important forlow temperature dynamics. At the end of this paper, we apply this technique tostudy a real helical chain magnet.