arXiv subjects

B. Keimer

Publications and source records attributed to B. Keimer.

309 records · Page 18Linked to original sources

arXiv1997

High energy spin excitations in YBa_2 Cu_3 O_{6.5}

Inelastic neutron scattering has been used to obtain a comprehensive description of the absolute dynamical spin susceptibility $χ'' (q,ω)$ of the underdoped superconducting cuprate YBa_2 Cu_3 O_{6.5} ($T_c = 52 K$) over a wide range of energies and temperatures ($2 meV \leq \hbar ω\leq 120 meV$ and $5K \leq T \leq 200K$). Spin excitations of two different symmetries (even and odd under exchange of two adjacent CuO_2 layers) are observed which, surprisingly, are characterized by different temperature dependences. The excitations show dispersive behavior at high energies.

cond-mat.supr-con↗

arXiv1997

Doping Dependence of the Magnetic Resonance Peak in YBa_2 Cu_3 O_{6+x}

We report inelastic neutron scattering experiments on the doping dependence of the energy and spectral weight of the sharp magnetic resonance peak in YBa_2 Cu_3 O_{6+x}. These measurements also shed light on the relationship between the magnetic excitations in the normal and superconducting states.

cond-mat↗

arXiv1996

Superconductivity-Induced Anomalies in the Spin Excitation Spectra of Underdoped YBa_2 Cu_3 O_{6+x}

Polarized and unpolarized neutron scattering has been used to determine the effect of superconductivity on the magnetic excitation spectra of YBa_2 Cu_3 O_{6.5} (T_c = 52K) and YBa_2 Cu_3 O_{6.7} (T_c = 67K). Pronounced enhancements of the spectral weight centered around 25 meV and 33 meV, respectively, are observed below T_c 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 YBa_2 Cu_3 O_7.

cond-mat.supr-con↗