Impurities in weakly coupled quantum spin chains Sr${}_2$CuO${}_3$ and SrCuO${}_2$

Abstract

We study the effect of non-magnetic Zn${}^{2+}$ (spin-$0$) and magnetic Ni${}^{2+}$ (spin-$1$) impurities on the ground state and low-lying excitations of the quasi-one-dimensional spin-$1/2$ Heisenberg antiferromagnet Sr${}_2$CuO${}_3$ using inelastic neutron scattering, specific heat and bulk magnetization measurements. We show that 1 \% Ni${}^{2+}$ doping in Sr${}_2$CuO${}_3$ results in a sizable spin gap in the spinon excitations, analogous to the case of Ni-doped SrCuO${}_2$ previously reported [ref. 1]. However, a similar level of Zn${}^{2+}$ doping in SrCuO${}_2$, investigated here for comparison, did not reveal any signs of a spin gap. Magnetic ordering temperature was found to be suppressed in the presence of both Zn${}^{2+}$ and Ni${}^{2+}$ impurities, however, the rate of suppression due to Ni${}^{2+}$ was found to be much more pronounced than for Zn${}^{2+}$. Effect of magnetic field on the ordering temperature is investigated. We found that with increasing magnetic field, not only the magnetic ordering temperature gradually increases but the size of specific heat anomaly associated with the magnetic ordering also progressively enhances, which can be qualitatively understood as due to the field induced suppression of quantum fluctuations.

Accepted in PRB

References in corpus (22)

• Defects in correlated metals and superconductors
• Spin-Orbital Separation in the quasi 1D Mott-insulator Sr2CuO3
• Reduction of ordered moment and Neel temperature of quasi one-dimensional antiferromagnets Sr2CuO3 and Ca2CuO3
• Thermal conductivity and specific heat of the linear chain cuprate Sr${}_2$CuO${}_3$: Evidence for thermal transport via spinons
• Spinons in the strongly correlated copper oxide chains in SrCuO2
• Electronic structure and magnetic properties of the linear chain cuprates Sr_2CuO_3 and Ca_2CuO_3
• Dirty-boson physics with magnetic insulators
• Anisotropic spin freezing in the S=1/2 zigzag ladder compound SrCuO2
• Neel order in doped quasi one-dimensional antiferromagnets
• Spin pseudogap in Ni-doped SrCuO2
• Evidence for Ballistic Thermal Conduction in the One-Dimensional S=1/2 Heisenberg Antiferromagnetic Spin System Sr2CuO3
• An Accurate Determination of the Exchange Constant in Sr_2CuO_3 from Recent Theoretical Results
• Disorder-induced Spin Gap in the Zigzag Spin-1/2 Chain Cuprate Sr_{0.9}Ca_{0.1}CuO_2
• Phase diagram of an impurity in the spin-1/2 chain: two channel Kondo effect versus Curie law
• Spin Gap in the Single Spin-1/2 Chain Cuprate Sr${}_{1.9}$Ca${}_{0.1}$CuO${}_3$
• 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${}_2$
• Crystal growth of the non-magnetic Zn${}^{2+}$ and magnetic Co${}^{2+}$ doped quasi one-dimensional spin chain compound SrCuO${}_2$ using the travelling solvent floating zone method
• Spin pseudogap in the $S=\frac{1}{2}$ chain material Sr${}_2$CuO${}_3$ with impurities
• Effects of quantum impurity spins on the magnetic properties of zigzag and linear spin chains
• Magnetic ordering in the ultra-pure site-diluted spin chain materials SrCu${}_{1-x}$Ni${}_x$O${}_2$
• Suppression of the impurity-induced local magnetism by the opening of a spin pseudogap in Ni-doped Sr${}_2$CuO${}_3$
• Relaxation time spectrum of low-energy excitations in one- and two-dimensional materials with charge or spin density waves

Cited by in corpus (5)

• Particle-hole asymmetry in the dynamical spin and charge structure factors of the corner-shared one-dimensional cuprates
• Multi-spinon and holon excitations probed by resonant inelastic x-ray scattering on doped one-dimensional antiferromagnets
• The dynamic structure factor in impurity-doped spin chains
• Novel magnetic phase in a weakly ordered spin-1/2 chain antiferromagnet Sr${}_2$CuO${}_3$
• Spin-$S$ impurities with XXZ anisotropy in a spin-1/2 Heisenberg chain