Single crystal electron paramagnetic resonance spectra of Cs2MnF6 and K2MnF6 diluted in the isomorphous germanium...

In this work single crystal electron paramagnetic resonance (EPR) spectra of Cs(2)MnF(6) and K(2)MnF(6) diluted in the similar germanium salts have been interpreted and fitted. The spectra of the cubic cesium salt were recorded with the magnetic field parallel with the 4-fold axis and with the 3-fold axis. The spectrum along the 4-fold axis looks as expected with six groups from the manganese nuclear spin each split into seven lines caused by the nuclear spin from the six fluorine ligands. The spectrum along the 3-fold axis contains considerably more lines. This can be explained by the fact that only the transitions with the M(S) values -1/2<-->1/2 are observed together with the fact that the nuclear Zeeman effect from the six fluorine ligands mixes states and makes forbidden transitions allowed. The spectra of the trigonal potassium salt are recorded along the 3-fold axis and perpendicular to this axis. The sign of the zfs parameter was determined by high frequency EPR spectroscopy at low temperature. The knowledge of this meant that we could determine the sign of the two fluorine hyperfine coupling parameters both in this case and in the cubic case.