The preparation of the KMeF3 (Me=Mn, Fe, Co, Ni) crystals for the studies by Moessbauer effect

A method of synthesizing KMnF3, KFeF3, CoF3 and KNiF3 crystals is described for investigating them by the Moessbauer method on the Fe57 isotope. Neel and Debye temperatures found for these crystals are given. The X-ray diffraction analysis of samples with a Fe57 impurity confirms their single-phase character. For pure KMnF3, KFeF3, KCoF3 and KNiF3 the lattice constants are 4.184+-0.003, 4.116+-0.004, 4.065+-0.004 and 4.011+-0.002 A0, respectively. The Moessbauer spectra (MS) of all the absorbers at T=295 K present a single line of the width GAMMA = 0.4-0.6 mm/s with an isomeric shift sigma = +1.48+-0.02 mm/s relative to the source of Co57(Cr). Line splitting in MS makes it possible to determine the temperature of magnetic transformation: Curie temperature for ferro- and ferrimagnetics and Neel temperature for antiferromagnetics. The dependence is presented of the number of γ-quanta passed through the KCoF3-Fe57 absorber on temperature at the source fixed velocity. The temperature of a drastic increase in the counting rate of γ-quanta corresponds to transformation of a crystal into a magneto-ordered state