Abstract
Neutron scattering experiments were carried out to explore Ni-impurity effects on static spin correlations in La2-xSrxCuO 4 in the vicinity of the superconductor-insulator boundary where both parallel and diagonal spin-density modulations (SDMs) coexist at low temperature. Dilute Ni substitution completely destroys the bulk superconductivity and alters well-defined incommensurate peaks of Ni-free SDMs into a single broad peak at (π,π). As the Ni concentration (y) reaches ∼x, the magnetic diffuse scattering is transformed to an intense sharp Bragg peak, corresponding to a three-dimensional antiferromagnetic (AF) order in bulk. TN of such Ni-induced AF order depends on x and appears to disappear at x ∼ 0:1. A simplified cross section for the Q spectra taking into account the orthorhombic domain structure reproduces the Ni-impurity effect on the static spin correlations well, which results in a decreasing incommensurability of both types of SDMs. These effects are approximately ascribed by a reduction in the number of mobile holes, or by the effective hole number xeff = x - y, similarly to the case of diagonal SDMs in insulating spin-glasses.
Original language | English |
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Article number | 074703 |
Journal | Journal of the Physical Society of Japan |
Volume | 76 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2007 |
Externally published | Yes |
Keywords
- Incommensurate spin correlations
- LaSrCuO
- Neutron scattering
- Ni
- Spin density modulation
- Substitution effect