Wakimoto S, Yamada K, Tranquada J M, Frost C D, Birgeneau R J, Zhang H
Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
Phys Rev Lett. 2007 Jun 15;98(24):247003. doi: 10.1103/PhysRevLett.98.247003. Epub 2007 Jun 11.
Magnetic excitations for energies up to approximately 100 meV are studied for overdoped La(2-x)Sr(x)CuO(4) with x=0.25 and 0.30, using time-of-flight neutron spectroscopy. Comparison of spectra integrated over the width of an antiferromagnetic Brillouin zone demonstrates that the magnetic scattering at intermediate energies, 20 <or= omega <or= 100 meV, progressively decreases with overdoping. This strongly suggests that the magnetism is not related to Fermi surface nesting, but rather is associated with a decreasing volume fraction of (probably fluctuating) antiferromagnetic bubbles.
