Finite-size effects in the quasi-one-dimensional quantum magnets Sr$_{2}$CuO$_{3}$, Sr$_{2}$Cu$_{0.99}$M$_{0.01}$O$_{3}$ (M = Ni, Zn), and SrCuO$_{2}$

TL;DR

This study investigates how finite-size effects and doping influence the magnetic properties of quasi-one-dimensional spin-1/2 Heisenberg antiferromagnets, revealing defect behaviors and the impact on magnetic ordering.

Contribution

It provides a detailed analysis of defect effects and finite-size influences on magnetic susceptibility in specific quasi-1D antiferromagnetic compounds, including doped and frustrated systems.

Findings

Ni acts as a scalar defect with screened spin in Sr$_{2}$Cu$_{0.99}$NiO$_{3}$

Doping reduces defect concentration compared to nominal values in Sr$_{2}$Cu$_{0.99}$ZnO$_{3}$

Doping influences low-temperature magnetic order and frustration effects in SrCuO$_{2}$

Abstract

We studied the finite-size effects on the magnetic behavior of the quasi-one-dimensional spin S = $\frac{1}{2}$ Heisenberg antiferromagnets Sr$_{2}$CuO$_{3}$, Sr$_{2}$Cu$_{0.99}$M$_{0.01}$O$_{3}$ (M = Zn and Ni), and SrCuO$_{2}$. Magnetic susceptibility data were analyzed to estimate the concentration of chain-breaks due to extrinsically doped defects and/or due to slight oxygen off-stoichiometry. We show that the susceptibility of Sr$_{2}$Cu$_{0.99}$Ni$_{0.01}$O$_{3}$ can be described by considering Ni$^{2+}$ as a scalar defect ($S_{eff}=0$) indicating that the Ni spin is screened. In Sr$_{2}$Cu$_{0.99}$Zn$_{0.01}$O$_{3}$ susceptibility analysis yields a defect concentration smaller than the nominal value which is in good qualitative agreement with crystal growth experiments. Influence of doping on the low-temperature long-range spin ordered state is studied. In the compound SrCuO$_{2}$, consisting of zigzag S = $\frac{1}{2}$ chains, the influence of spin frustration on the magnetic ordering and the defect concentration determined from the susceptibility data is discussed.