The Mössbauer and magnetic resonances investigations of structural phase transitions in K ZnCl crystals

Abstract

The experimental data carried out by Mossbauer and magnetic resonances investigations of the structural phase transitions in K2ZnCl4 crystals are discussed by a simple electrostatic model, calculating, the lattice contributions to the local electric potential V(r), electric field intensity E(r) and electric field gradient tensor, \(\)(r) and taking into account both the fractional electric point charges and rigid lattice approximations. The validity of the model is proved by a good fit of the computing results and experimental data of quadrupole splitting parameters at K sites obtained by 39K-NMR methods in high temperature incommensurate phase (\(\) Pnam symmetry). The experimental results obtained by Mossbauer and EPR methods in commensurate phase (Pna21symmetry) of iron and copper doped K2ZnCl4 crystals are explained by relaxing the rigid lattice approximation. The insertion of probe ions appear to be done on not-exactly-Zn2+ site.