Neutron crystal-field spectroscopy and magnetic properties of DyBa2Cu3O7- delta.

Abstract

Inelastic neutron scattering has been employed to study the crystalline electric-field (CEF) interaction in the high-${T}_{c}$ superconductor $\mathrm{Dy}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$. The CEF at the Dy site splits the 16-fold degeneracy of the ground-state $J$ multiplet into eight doublet states. From the observed energy spectra we have been able to assign the four lowest excited CEF states which provided sufficient information to derive the leading CEF parameters. The results are used to predict both the direction and the size of the ordered magnetic moment in zero field, the high-field magnetization, and the Schottky anomaly of the heat capacity of Dy${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$, which yields reasonable agreement with the experimental data. The character of the CEF level scheme supports the application of the two-dimensional Ising model to describe the magnetic ordering of the Dy moments. From the temperature dependence of the quasielastic linewidth we conclude that the conduction electron density is negligibly small at the Dy site below ${T}_{c}$.