Direct observation of impurity-induced magnetism in an S = 1/2 antiferromagnetic Heisenberg 2-leg spin ladder

TL;DR

This study uses NMR and magnetization measurements to directly observe how impurities induce local magnetism in a S=1/2 antiferromagnetic two-leg spin ladder, revealing temperature-dependent magnetic variations near impurity sites.

Contribution

It provides the first direct experimental evidence of impurity-induced magnetism in a spin ladder system, supported by quantum Monte Carlo calculations.

Findings

Impurities cause significant changes in NMR lineshapes.

Local magnetization varies with temperature near impurity sites.

Model calculations support experimental observations.

Abstract

Nuclear magnetic resonance and magnetization measurements were used to probe the magnetic features of single-crystalline Bi(Cu(1-x)Znx)2PO6 with 0<x<0.05 at temperatures between 2.6 K and 300 K. The simple lineshape of the 31P NMR signals of the pristine compound changes considerably for x>0 and we present clear evidence for a temperature dependent variation of the local magnetization close to the Zn sites. The generic nature of this observation is indicated by results of model calculations on appropriate spin systems of limited size employing QMC methods.