High-energy Cu spin excitations in PrBa2Cu3O6+x

TL;DR

This study investigates high-energy magnetic excitations in PrBa2Cu3O6+x using neutron scattering, revealing detailed magnon dispersion and exchange interactions, with findings consistent across different oxygen doping levels.

Contribution

It provides the first detailed measurement of magnon dispersion and exchange constants in PrBa2Cu3O6+x, highlighting similarities and differences with related compounds.

Findings

J_parallel = 127 +/- 10 meV

J_perp = 5.5 +/- 0.9 meV

Exchange constants are doping-independent

Abstract

This paper describes high-energy neutron inelastic scattering measurements of propagating magnetic excitations in PrBa2Cu3O6+x (x approx 0.2 and 0.93). The measurements probe the acoustic and optic modes of the antiferromagnetically-ordered copper--oxygen bilayers in the energy range 50-150 meV. The observed magnon dispersion can be described satisfactorily in this energy range by a spin wave model including intra- and inter-layer nearest-neighbour exchange constants J_parallel and J_perp. We find J_parallel = 127 +/- 10 meV and J_perp = 5.5 +/- 0.9 meV. The value of J_parallel is virtually the same as that found in YBa2Cu3O6.2, but J_perp is a factor of two smaller. To within experimental error the values of J_parallel and J_perp for PrBa2Cu3O6+x do not vary with oxygen doping.