Magnetization profiles and NMR spectra of doped Haldane chains at finite temperatures

Open segments of S=1 antiferromagnetic spin chains are studied at finite temperatures and fields using continuous time quantum Monte Carlo techniques. By calculating the resulting magnetization profiles for a large range of chain lengths with fixed field and temperature we reconstruct the experimentally measured NMR spectrum of impurity doped Y2BaNi1-xMgxO5. For temperatures above the gap the calculated NMR spectra are in excellent agreement …