Speaker
Description
The Oxyhalides of rare earth elements (LnOHal; Ln- lanthanide; Hal = F; Cl; Br; are very interesting materials which find various applications as X-ray luminescent,screens, as anti-Stokes (frequency up shift) converters, commercial phosphors, displays and photosimulated materials.
Magnetic coupling between Ln$^{3+}$ ions is usually weak resulting in a Curie–Weiss type paramagnetic behaviour down to low temperatures. It is thus difficult to infer with certainty the nature or even the temperature of the magnetic ordering. The strong anisotropy of the rare earth oxyhalide structure may also be reflected in the magnetic properties.
The Ln$^{3+}$ ions have low-lying multiplets with high $J$-values and when these are split further by the strong crystal field of uniaxial C4v symmetry in LnOHal interesting magnetic phenomena might be observed.
The susceptibilities of EuOCl and EuOBr follow the paramagnetic Curie–Weiss behavior down to low temperatures. The temperature dependence of the experimental paramagnetic susceptibility for EuOCl and EuOBr was simulated with the aid of the van Vleck Formalism.
