Phys. Rev. Lett. 78, 713–716 (1997)Superconductivity-Induced Anomalies in the Spin Excitation Spectra of Underdoped YBa2Cu3 O6+xReceived 23 August 1996; published in the issue dated 27 January 1997 Polarized and unpolarized neutron scattering have been used to determine the effect of superconductivity on the magnetic excitation spectra of YBa2Cu3O6.5 (Tc = 52 K) and YBa2Cu3O6.7 (Tc = 67 K). Pronounced enhancements of the spectral weight centered around 25 and 33 meV, respectively, are observed below Tc in both crystals, compensated predominantly by a loss of spectral weight at higher energies. The data provide important clues to the origin of the 40 meV magnetic resonance peak in YBa2Cu3O7. © 1997 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.78.713
DOI:
10.1103/PhysRevLett.78.713
PACS:
74.25.Jb, 74.25.Kc, 74.72.Bk
|
