Far-infrared properties and magnetic excitations in PrBa2Cu3O6

Dynamic properties and magnetic excitations in PrBa2Cu3O6 were investigated by means of a quasi-optical submillimeter backward-wave-oscillator technique and a Fourier spectrometer at the wavelengths ν = 4-33 and 50-650 cm-1, respectively. A weak and wide absorption line was observed in the submillimeter transmission spectra near 15 cm-1 at T < 70 K, which was identified as a rare-earth mode originating from electronic transitions between the low-energy crystal-field states of Pr3-. Temperature dependence of the resonance frequency, linewidth and mode contribution to static magnetic permeability were obtained. Dynamic magnetic susceptibility χ(ω,q,T) and resonance frequencies ω(q,T) of the magnetic excitations of the Pr-subsystem were calculated and analyzed above and below the Neel temperature (TN = 10 K). (orig.)