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

TL;DR

This paper investigates the low-temperature magnetic behavior of a class of single-chain magnets with alternating isotropic and anisotropic units, using a transfer matrix approach to account for quantum effects and inter-chain interactions.

Contribution

It introduces a transfer matrix method to analyze thermodynamic properties of SCMs with non-collinear anisotropy axes and weak inter-chain interactions, including real material application.

Findings

Transfer matrix method effectively models low-temperature behavior.

Weak inter-chain interactions can be incorporated into the model.

Application to a real helical chain magnet demonstrates practical relevance.

Abstract

Here we study thermodynamic properties of an important class of single-chain magnets (SCMs), where alternate units are isotropic and anisotropic with anisotropy axes being non-collinear. This class of SCMs shows slow relaxation at low temperatures which results from the interplay of two different relaxation mechanisms, namely dynamical and thermal. Here anisotropy is assumed to be large and negative, as a result, anisotropic units behave like canted spins at low temperatures; but even then simple Ising-type model does not capture the essential physics of the system due to quantum mechanical nature of the isotropic units. We here show how statistical behavior of this class of SCMs can be studied using a transfer matrix (TM) method. We also, for the first time, discuss in detail how weak inter-chain interactions can be treated by a TM method. The finite size effect is also discussed which becomes important for low temperature dynamics. At the end of this paper, we apply this technique to study a real helical chain magnet.