Model for spin coupling disorder effects on the susceptibility of antiferromagnetic nanochains

TL;DR

This study examines how exchange disorder affects the magnetic susceptibility of antiferromagnetic nanochains, revealing conditions under which chains mimic single spins and how size influences this behavior.

Contribution

It introduces a simple criterion based on susceptibility to determine when odd-sized chains behave like isolated spin-1/2 particles.

Findings

At low temperatures, chains act like isolated spins.

Increasing chain size leads to thermodynamic limit behavior.

A criterion is provided to identify when chains simulate single spins.

Abstract

The temperature dependence of the static magnetic susceptibility of exchange-disordered antiferromagnetic Heisenberg spin-1/2 finite chains with an odd number of spins is investigated as a function of size and type of disorder in the exchange coupling. Two models for the exchange disorder distribution are considered. At sufficiently low temperatures each chain behaves like an isolated spin-1/2 particle. As the size of the chains increases, this analogy is lost and the chains evolve into the thermodynamic limit behavior. The present study provides a simple criterion, based on susceptibility measurements, to establish when odd-sized chains effectively simulate a single spin-1/2 particle.