Analysis of the ESR spectrum of manganese (II) in the layered compound Cd₂P₂Se₆

The Q-band and X-band ESR spectra of Mn²⁺ in the layered compound Cd₂P₂Se₆ are reported. The Mn²⁺ is in a trigonal environment coordinated to six selenium atoms. The parameters of the spin hamiltonian have been determined and reasonable agreement is obtained between theory and experiment with g_| = 2.01, g_⊥ = 2.05, |D| = 0.286 cm^-1, |A| = 70.0 × 10^-4 cm^-1. The results of the ESR analysis are compared with previous studies of the analogous layered compound Cd₂P₂S₆. The Mn(II) crystal-field splitting parameter D increases approximately eight-fold from that in the sulfide lattice. The exceptionally large crystal-field splitting is correlated with the layered structure of the lattice and the MnSe bond covalency. It is concluded that the dominant effect is that of the bond covalency.