Magnetic excitations and structural change in the S=1/2 quasi-one-dimensional magnet Sr_{14-x}Y_{x}Cu_{24}O_{41} (0<x<1)

TL;DR

This study investigates how yttrium substitution affects magnetic excitations and structural properties in the quasi-one-dimensional Sr_{14-x}Y_{x}Cu_{24}O_{41} system using neutron scattering, revealing changes in dimerized states and chain sliding behavior.

Contribution

It provides new insights into the effects of yttrium doping on magnetic and structural dynamics in Sr_{14-x}Y_{x}Cu_{24}O_{41}, highlighting the instability of dimerized states and chain sliding phenomena.

Findings

Yttrium substitution broadens inelastic peaks from dimerized states.

Dimerized state becomes unstable with yttrium doping.

Chain sliding along the c axis varies with temperature and yttrium content.

Abstract

Neutron scattering measurements have been performed on the S=1/2 quasi-one-dimensional system Sr_{14-x}Y_{x}Cu_{24}O_{41}, which has both simple chains and two-leg ladders of copper ions. We observed that when a small amount of yttrium is substituted for strontium, which is expected to reduce the number of holes, the dimerized state and the structure in the chain are changed drastically. The inelastic peaks originating from the dimerized state of the chain becomes broader in energy but not in momentum space. This implies that the dimerized state becomes unstable but the spin correlations are unchanged with yttrium substitution. Furthermore, it was observed that nuclear Bragg peak intensities originating from the chain show strong temperature and x dependence, which suggests that the chains slide along the c axis as temperature and x are varied.