Magnetic structure of the frustrated S=1/2 chain magnet LiCu2O2 doped with nonmagnetic Zn

TL;DR

This study investigates how nonmagnetic Zn doping affects the magnetic structure of the frustrated S=1/2 chain magnet LiCu2O2, revealing a transition from a planar spin structure to a spin glass-like state with short-range correlations.

Contribution

It provides detailed experimental insights into the magnetic phase evolution of LiCu2O2 upon Zn doping using magnetization, ESR, and NMR techniques.

Findings

Single-phase crystals are maintained for x<0.12 Zn doping.

ESR spectra indicate a planar spin structure with uniaxial anisotropy.

Highly doped samples exhibit a spin glass-like magnetic structure with short-range spiral correlations.

Abstract

We present the results of magnetization, ESR and NMR measurements on single crystal samples of the frustrated S=1/2 chain cuprate LiCu2O2 doped with nonmagnetic Zn^2+. As shown by the x-ray techniques the crystals of Li(Cu{1-x}Zn{x})2O2 with x<0.12 are single-phase, whereas for higher Zn concentrations the samples were polyphase. ESR spectra for all monophase samples (0<= x<0.12) can be explained within the model of a planar spin structure with a uniaxial type anisotropy. The NMR spectra of the highly doped single crystal sample Li(Cu0.9Zn0.1)2O2 can be described in the frame of a planar spin glass like magnetic structure with short range spiral correlations in the crystal (ab)-planes with strongest exchange bonds. The value of magnetic moments of Cu^2+ ions in this structure is close to value obtained for undoped crystals: (0.8 +- 0.1) mu_B.