Portal de Periódicos da CAPES

Exchange interactions in mixed Yb 3 + - Cr 3 + </mml:msup…

1993; American Physical Society; Volume: 48; Issue: 17 Linguagem: Inglês

10.1103/physrevb.48.12723

1095-3795

Michael Aebersold, Hans U. Güdel, Andreas Hauser, A. Fürrer, H. Blank, Richard Kahn,

Physics of Superconductivity and Magnetism

The two title compounds were synthesized and investigated with the inelastic-neutron-scattering (INS) technique. They contain mixed YbM${\mathrm{Br}}_{9}^{3\mathrm{\ensuremath{-}}}$ (M=${\mathrm{Cr}}^{3+}$, ${\mathrm{Ho}}^{3+}$) dimers as discrete units, and the magnetic excitations of mixed ${\mathrm{Yb}}^{3+\mathrm{\ensuremath{-}}}$${\mathrm{Cr}}^{3+}$ and ${\mathrm{Yb}}^{3+\mathrm{\ensuremath{-}}}$${\mathrm{Ho}}^{3+}$ dimers could thus be observed. The ${\mathrm{Yb}}^{3+\mathrm{\ensuremath{-}}}$${\mathrm{Cr}}^{3+}$ dimer has three INS transitions, for which anisotropic exchange, as well as zero-field splitting of ${\mathrm{Cr}}^{3+}$, has to be included in the exchange Hamiltonian. For the ${\mathrm{Yb}}^{3+\mathrm{\ensuremath{-}}}$${\mathrm{Ho}}^{3+}$ dimer the effect of the exchange interaction manifests itself as a broadening and a splitting of the crystal-electric-field levels of the isolated ${\mathrm{Ho}}^{3+}$ ion. Taking into account the full (2J+1) ground-state multiplet of ${\mathrm{Ho}}^{3+}$, as well as anisotropic exchange, gives a satisfactory description of this dimer.