Magnetic resonance in pure and diamagnetically diluted spin-Peierls CuGeO3

Magnetic resonance at frequencies 22-75 GHz is investigated in pure single-crystalline CuGeO3 in the temperature range 1.2-25 K. At temperatures below 4 K the magnetic resonance line splits into four spectral components. The line close to the ESR of the paramagnetic phase is associated with impurities or defects. The other three lines have the same intensity in different samples and are apparently characteristic for pure single crystals at low temperature. An antiferromagnetic resonance with two resonance absorption branches and a spectrum characteristic for an antiferromagnet with easy, average, and hard anisotropy axes was observed and investigated in the Neel compound Cu0.98Zn0.02GeO3 with diamagnetic dilution of the spin subsystem. (C) 1996 American Institute of Physics.