Spin-Waves in the Mid-Infrared Spectrum of Antiferromagnetic YBa${}_2$Cu${}_3$O${}_{6.0}$

Abstract

The mid-infrared spin-wave spectrum of antiferromagnetic YBa${}_2$Cu${}_3$O${}_{6.0}$\ was determined by infrared transmission and reflection measurements ($\bbox{k} \!\! \parallel $c) at $T=10$~K.\@ Excitation of single magnons of the optical branch was observed at $E_{\text{op}}=178.0$~meV.\@ Two further peaks at $346$~meV ($\approx 1.94E_{\text{op}}$) and $470$~meV ($\approx 2.6E_{\text{op}}$) both belong to the two-magnon spectrum. Linear spin wave theory is in good agreement with the measured two-magnon spectrum, and allows to determine the exchange constant $J$ to be about $120$~meV, whereas the intrabilayer coupling $J_{12}$ is approximately $0.55J$.

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References in corpus (5)

• Spin Gaps and Spin Dynamics in La_{2-x}Sr_xCuO_4 and YBa_2Cu_3O7_δ
• Order-Disorder Transition in a Two-Layer Quantum Antiferromagnet
• Phonon Assisted Multimagnon Optical Absorption and Long Lived Two-Magnon States in Undoped Lamellar Copper Oxides
• Spin Gaps and Bilayer Coupling in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ and YBa${}_2$Cu${}_4$O${}_8$
• Theory of Anisotropic Superexchange in Insulating Cuprates

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• Optical absorption spectra in SrCu_2O_3 two-leg spin ladder