Spin excitations and phonons in YBa 2Cu 3O 6+ x: A status report

Abstract

A review is made of recent developments in inelastic neutron scattering experiments on spin excitations and phonons in the high-temperature superconductor YBa 2Cu 3O 6+ x and its antiferromagnetic precursor YBa 2Cu 3O 6.2. These experiments include the detection of high-energy “optical” spin waves and the determination of the full spin Hamiltonian in YBa 2Cu 3O 6.2, detailed investigations of the 40 meV magnetic resonance peak in the superconducting state of YBa 2Cu 3O 7 and its precursors in underdoped YBa 2Cu 3O 6+ x , and experiments on the effect of superconductivity on phonon lifetimes in YBa 2Cu 3O 7.