Paramagnonlike excitations and spin diffusion in magnetic resonance studies of copper oxide superconductors

Abstract

The relaxation function theory for a doped two-dimensional Heisenberg antiferromagnetic system in the paramagnetic state for all wave vectors through the Brillouin zone is presented in view of low frequency response of high-$T_c$ copper oxide superconductors. We deduced the regions of long lifetime [$T\lesssim 400(1-4x)$ K] and "overdamped" [$T\gtrsim 700(1-4x)$ K] paramagnonlike excitations in the temperature ($T$)-doping index ($x$) phase diagram from plane oxygen nuclear spin-lattice relaxation rate ${}^{17}(1/T_1)$ data in up to optimally doped La${}_{2-x}$Sr${}_x$CuO${}_4$ thus providing the regimes for the spin wave concept and the ''overdamped'' mode.

Physical Review B, accepted, in press

References in corpus (3)

• Disappearance of antiferromagnetic spin excitations in over-doped La${}_{2-x}$Sr${}_x$CuO${}_4$
• Resonant magnetic excitations at high energy in superconducting $\mathbf{YB}{\mathbf{a}}_2\mathbf{C}{\mathbf{u}}_3{\mathbf{O}}_{6.85}$
• Absence of an isotope effect in the magnetic resonance in high-$T_c$ superconductors