Effects of Quantum Spin-1/2 Impurities on the Magnetic Properties of Zigzag Spin Chains.
We investigate the effect of Co^{2+} (spin-1/2) impurities on the magnetic ground state and low-lying spin excitations of the quasione-dimensional spin-1/2 antiferromagnet SrCuO_{2} by means of neutron scattering, muon spin spectroscopy, and bulk (ac and dc) magnetic susceptibilities. We found that dilute Co doping induces an Ising-like anisotropy and enhances the magnetic ordering temperature rather significantly, but preserves the gapless nature of the spin excitations. These results are in apparent contradiction with the recent studies of Ni (spin-1) doped SrCuO_{2}. Low-temperature magnetic behavior of the Co-doped zigzag chains in SrCuO_{2} reveals the presence of a weak geometrical spin frustration.
Indian Institute of Science Education and Research, Pune, Maharashtra-411008, India.
Koushik
K
Karmakar
Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.|Heinz Maier-Leibnitz Zentrum (MLZ) and Physics Department E21, Technische Universität München, D-85748 Garching, Germany.
Markos
M
Skoulatos
Center for Transport and Devices of Emergent Materials, TU Dresden, D-01062 Dresden, Germany.|Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden, Germany.
Giacomo
G
Prando
Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Bertran
B
Roessli
Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Uwe
U
Stuhr
Dipartimento di Fisica and Unità CNISM di Pavia, I-27100 Pavia, Italy.|Institute for Solid State Physics, Dresden Technical University, TU-Dresden, 01062 Dresden, Germany.
Franziska
F
Hammerath
Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.|Department of Quantum Matter Physics, University of Geneva, 1211 Geneva, Switzerland.
Christian
C
Rüegg
Indian Institute of Science Education and Research, Pune, Maharashtra-411008, India.
Surjeet
S
Singh