EPR study of Dy~(3+) ions in dyBa_2Cu_3O_(6+x)

摘要

Concentrated polycrystalline DyBa_2Cu_3O_(6+x) compounds are studied by X-band EPR spectroscopy. A broad resonance line due to the highly anisotropic EPR spectrum of Dy~(3+) ions is identified on several specimens at low temperatures. Powder simulation of the EPR spectra complies with the ground Kramers doublet predicted by crystal field analysis of Dy~(3+) ions. Calculations of the second and fourth moments of the resonance lines due to the dipole-dipole interactions of Dy~(3+) indicate the presence of substantial exchange narrowing of the dipolar-broadened EPR linewidth.