ANTIFERROMAGNETIC-RESONANCE IN THE (K1-XNAX)MNF3 AND (K1-XLIX)MNF3 SYSTEMS

The X-band antiferromagnetic resonance (AFMR) Spectrum of KMnF3 with L i+ and Na+ impurities was studied at temperatures from 40 K to T(N). F rom comparison of the AFMR measurements with results of x-ray studies for the same good-quality crystals it was found that complete coincide nce between the magnetic and structural phase transitions does not occ ur, It was also ascertained that, for T < T(N), low-temperature magnet ic phase transitions are highly sensitive to the presence of even smal l quantities of impurities. Consequently, these transitions depend mar kedly on the quality of the samples analysed.