Magnetic susceptibility of diluted pyrochlore and SCGO antiferromagnets

TL;DR

This paper develops an accurate theoretical model for the magnetic susceptibility of diluted pyrochlore and SCGO antiferromagnets, explaining experimental phenomenology through short-range correlation analysis.

Contribution

It introduces a new approximate expression for magnetic susceptibility in diluted pyrochlore systems, extending the theory to SCGO and clarifying previous phenomenological models.

Findings

Derived an accurate susceptibility expression valid at all temperatures.

Extended the model to explain SCGO experimental data.

Provided theoretical support for phenomenological models.

Abstract

We investigate the magnetic susceptibility of the classical Heisenberg antiferromagnet with nearest-neighbour interactions on the geometrically frustrated pyrochlore lattice, for a pure system and in the presence of dilution with nonmagnetic ions. Using the fact that the correlation length in this system for small dilution is always short, we obtain an approximate but accurate expression for the magnetic susceptibility at all temperatures. We extend this theory to the compound SrCr_{9-9x}Ga_{3+9x}O_{19} (SCGO) and provide an explanation of the phenomenological model recently proposed by Schiffer and Daruka [Phys. Rev. B56, 13712 (1997)].