The wide-bandgap АIIBVI compounds doped with iron group transition metals (Mn, Cr, Ni, Fe) and their solid alloys are interesting from the standpoint of basic research and their practical use in semiconductor detectors, lasers and spintronic applications [1]. Magnetic and photoluminescent properties of ZnSe:Mn crystals with different Mn concentrations were investigated. The concentration of Mn2+ ions in ZnSe crystals has been varied from 0.01 to 0.3 at.%.figureFig. 1. Temperature dependence of inverse magnetic susceptibility for ZnSe:Mn crystals with different manganese concentrations. Н = 67 Gauss.Fig. 1 presents the temperature dependence of inverse magnetic susceptibility χ-1 for ZnSe:Mn crystals with different Mn concentrations. The figure shows that for all ZnSe:Mn crystals the magnetic susceptibility exhibits paramagnetic behavior, obeying the Curie-Weiss law: T x C x T x С x 0 0 ( ) ( ) + Θ = −Θ χ = . (1) For all ZnSe:Mn samples, the high-temperature linear part of the χ-1(T) dependence intercepts the temperature axis at negative values for the Curie-Weiss temperature Θ(x) that indicate the presence of antiferromagnetic interactions in ZnSe:Mn crystals. Magnetic properties studies have shown that at high doping levels the manganese atoms form Mn-Mn clusters in ZnSe. The photoluminescence (PL) spectra of ZnSe:Mn crystals reveal the presence of PL lines with maxima at 616 nm and 633 nm, which correspond to intracentre 4T2→6A1 and 4T1→6A1 transitions of Mn2+ ions respectively. It was established that for the lightly-doped ZnSe:Mn crystals, the intensity of “red” PL bands related with Mn2+ ions increases (Fig. 2) with increasing manganese concentration (< 0.06 at.% Mn), and in the heavily-doped ZnSe:Mn crystals the intensity of these bands decreases with increasing Mn concentration (> 0.06 at.% Mn). The observed concentration quenching of the PL bands related to Mn2+ ions in ZnSe:Mn crystals is due to the formation of Mn-Mn clusters at high levels of Mn concentration.figureFig. 2. Influence of Mn concentration on the intensity of PL bands with maxima at 616 nm (2) and 633 nm (1). T = 10 K (a). T = 300 K (b).[1] J.K. Furdyna. J. Appl. Phys. 64 (1988) R29.