Renormalization of Commensurate Magnetic Peak in Ni-doped La$_{1.85}$Sr$_{0.15}$CuO$_{4}$

M. Matsuura; M. Kofu; H. Kimura; K. Hirota

doi:10.1143/JPSJ.78.114703

paper

Renormalization of Commensurate Magnetic Peak in Ni-doped La $_{1.85}$ Sr $_{0.15}$ CuO $_{4}$

arXiv:0907.2742 · doi:10.1143/JPSJ.78.114703

Abstract

We have studied the magnetic excitations in impurity doped La $_{1.85}$ Sr $_{0.15}$ Cu $_{1 - y}$ A $_{y}$ O $_{4}$ (A=Ni or Zn) by neutron scattering. The dispersion for Zn: $y = 0.017$ is similar to that for the impurity free sample: incommensurate peaks with the incommensurability $δ = 0.12 \pm 0.01$ (rlu) do not change their positions up to 21 meV. On the other hand, for Ni: $y = 0.029$ , two incommensurate peaks observed at low energies suddenly change into a broad commensurate peak at $E_{cross} = 15$ meV. Compared to the impurity free sample with a similar Sr-concentration $x = 0.16$ , [B. Vignolle {\it et al.} Nature Physics {\bf 3} (2007) 163], $E_{cross}$ for Ni: $y = 0.029$ is decreased by nearly the same factor for the reduction in $T_{c}$ . This is very similar to the shift of the resonance energy ( $E_{res}$ ) in Ni-doped YBa $_{2}$ Cu $_{3}$ O $_{7}$ .[Y. Sidis {\it et al.}: Phys. Rev. Lett. {\bf 84} (2000) 5900]. These common impurity effects on the shift of $E_{cross}$ and $E_{res}$ suggest the same magnetic origin for the resonance peak in YBa $_{2}$ Cu $_{3}$ O $_{δ}$ and that for a crossing point of upward and downward dispersions in the La $_{2 - x}$ Sr $_{x}$ CuO $_{4}$ . We propose that the sudden change in the dispersion is better described by a crossover from incommensurate spin fluctuations to a gapped spin wave rather than a hourglass-like dispersion.

11 pages, 5 figures

References in corpus (8)

Cited by in corpus (1)

Progress in Neutron Scattering Studies of Spin Excitations in High-Tc Cuprates

Renormalization of Commensurate Magnetic Peak in Ni-doped La1.85​Sr0.15​CuO4​

Abstract

References in corpus (8)

Cited by in corpus (1)

Renormalization of Commensurate Magnetic Peak in Ni-doped La $_{1.85}$ Sr $_{0.15}$ CuO $_{4}$