Effects of quantum impurity spins on the magnetic properties of zigzag and linear spin chains

Abstract

We investigated the magnetic ground state and low-energy excitations of the spin chains compounds SrCuO${}_2$ (zigzag chains) and Sr${}_2$CuO${}_3$ (linear chains) in the presence of quantum impurities induced by lightly doping ($\le 1\%$) with Zn${}^{2+}$ ($S=0$), Co${}^{2+}$ ($S=1/2$) and Ni${}^{2+}$ ($S=1$) impurities at the Cu${}^{2+}$ site. We show that the ground states and the nature of low-lying excitations (i.e., gapped or gapless) depend on the spin state and symmetry of the defects. For Ni doped chains a spin gap is observed but for Zn and Co doping the excitations remain gapless. Co-doped chains exhibit magnetic order with critical temperatures significantly enhanced compared to those of the pristine compounds. In the specific case of 1 \% Co impurities, the linear chains exhibit long-range order below 11 K, while the zigzag chain is characterized by a quasi-long range ordered phase below 6 K with correlation lengths of about 12\textit{a} and 40\textit{c} units along the crystal axes \textit{a} and \textit{c}, respectively. The different magnetic behaviours of these two compounds with comparable intra- and interchain couplings underpin the role of spin frustration in the zigzag chains.

5 pages, 4 figures

References in corpus (10)

• Novel ordering of an S = 1/2 quasi one-dimensional Ising-like anitiferromagnet in magnetic field
• Dirty-boson physics with magnetic insulators
• Longitudinal SDW order in a quasi-1D Ising-like quantum antiferromagnet
• Magnetic correlations of the quasi-one-dimensional half-integer spin-chain antiferromagnets Sr$M_2$V${}_2$O${}_8$ ($M$ = Co, Mn)
• Spin pseudogap in Ni-doped SrCuO2
• 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
• Impact of strong disorder on the static magnetic properties of the spin-chain compound BaCu2SiGeO7
• 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${}_3$

Cited by in corpus (6)

• Spectroscopic signatures of next-nearest-neighbor hopping in the charge and spin dynamics of doped one-dimensional antiferromagnets
• Impurities in weakly coupled quantum spin chains Sr${}_2$CuO${}_3$ and SrCuO${}_2$
• The effect of different in-chain impurities on the magnetic properties of the spin chain compound SrCuO${}_2$ probed by NMR
• The dynamic structure factor in impurity-doped spin chains
• Boundary logarithmic corrections to the dynamical correlation functions of one-dimensional spin-1/2 chains
• Incommensurate-commensurate magnetic phase transition in the double tungstate Li2Co(WO4)2