Bilayer coupling in the yttrium-barium family of high-temperature superconductors
Bilayer coupling in the yttrium-barium family of high-temperature superconductors
We derive the expressions needed to interpret experiments relating to interplane magnetic coupling in YBa$_{2}$Cu$_{3}$O$_{6+x}$ and related materials, and use the results to interpret measurements of the optical magnon energy in YBa_{2}Cu_{3}O_{6.2} and of the NMR ``cross-relaxation" rate in Y_2Ba_{4}Cu_{7}O_{15}. We estimate $J_{\perp}\sim 14$ meV in both materials, and $\chi_{max}/\mu^2_{B} …