# Static and Dynamic Magnetic Properties of Spin-1/2 Inequilateral Diamond-Chain Compounds $A_3$Cu$_3$AlO$_2$(SO$_4$)$_4$ ($A$=K, Rb, and Cs)

## TL;DR

This study investigates the magnetic properties of spin-1/2 inequilateral diamond-chain compounds, revealing that a dimer-monomer chain model effectively describes their magnetic behavior without frustration.

## Contribution

The paper introduces a simplified dimer-monomer chain model to explain the magnetic properties of A3Cu3AlO2(SO4)4 compounds, highlighting the role of dimers and nearly isolated chains.

## Key findings

- Magnetic susceptibility varies with temperature and is explained by the model.
- The model accurately reproduces magnetization curves and excitation spectra.
- Dimer-monomer chain without frustration effectively describes the compounds' magnetism.

## Abstract

Spin-1/2 compounds A3Cu3AlO2(SO4)4 (A=K, Rb, and Cs) have one-dimensional (1D) inequilateral diamond chains. We analyze the temperature dependence of the magnetic susceptibility and determine the magnetic exchange interactions. In contrast to the azurite, a dimer is formed on one of the sides of the diamond. From numerical analyses of the proposed model, we find that the dimer together with a nearly isolated 1D Heisenberg chain characterizes magnetic properties including magnetization curve and magnetic excitations. This implies that a dimer-monomer composite chain without frustration is a good starting point for describing these compounds.