Interaction of Manganese Activator Ions in Zinc-Orthosilicate Phosphors

A study was made of specially prepared rhombohedral Zn₂SiO₄: Mn phosphors, utilizing magnetic, chemical, and luminescence techniques. From measurements of Weiss constants, it is shown that magnetic interaction occurs between manganese activator ions. The magnetic interaction increases with increasing proportion of manganese in the range where the following related luminescence characteristics decrease: (1) efficiency, (2) temperature break-point, and (3) decay time.An analysis of the magnetic data shows that isolated noninteracting manganese activator ions have five unpaired electrons, corresponding to Mn²⁺, and μ=5.90 Bohr magnetons (5.92 theoretical).The molar diamagnetic susceptibility of zinc-orthosilicate was determined as being (-64.6±{}0.7)×{}10^-6.