1999/12/29 by Chul-Ho Lee, Kazuyoshi Yamada, Yasuo Endoh +7 · 1 citation
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Superconductivity in MgB2 and Alloys #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1143/jpsj.69.1170
published as J. Phys. Soc. Jpn. 69 (2000) 1170 · 15 pages, 8 figures, revtex
arxiv created 1999/12/29 · openalex publication_date 2000/04/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The energy spectrum of incommensurate spin fluctuations in superconducting Sr-doped La2CuO4 has been studied by inelastic neutron scattering experiments. An energy gap in the spin excitation spectrum is observed in the superconducting state of optimally doped (x=0.15) and slightly overdoped (x=0.18) samples. At temperatures well below Tc, the incommensurate peaks diminish rapidly in intensity with decreasing energy below ~8meV and merge into the background below ~3.5meV for x=0.15 and ~4.5meV for x=0.18. For both samples, the energy spectrum of the q-integrated spin susceptibility, x"(w), exhibits an enhancement around 7meV, which is caused by a broadening in the momentum width of the incommensurate peaks. The gap-like structure in the energy spectrum and the enhancement of x"(w) survive at Tc. On the other hand, for both underdoped (x=0.10) and heavily overdoped (x=0.25) samples there is neither a clear energy gap nor an enhancement of x"(w) below Tc.