Berlin 2018 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
MA: Fachverband Magnetismus
MA 21: Poster I
MA 21.71: Poster
Tuesday, March 13, 2018, 09:30–13:00, Poster A
Magnetic properties of chain antiferromagnets KFeS2 and RbFeSe2 — •Zakir Seidov1,2, Vladimir Tsurkan3, Hans-Albrecht Krug von Nidda1, Irina Filipova3, Dorina Croitori3, Axel Günther1, Airat Kiiamov4, Lenar Tagirov4,5, Farit Vagizov4, Tatyana Gavrilova5, and Alois Loidl1 — 1EP V, EKM, University of Augsburg, D-86135 Augsburg — 2Institute of Physics, ANAS, AZ-1143 Baku — 3Institute of Applied Physics, Academy of Sciences of Moldova, MD-20208 Chisinau — 4Institute of Physics, Kazan Federal University, RUS-420008 Kazan — 5E.K.Zavoisky Physical-Technical Institute, RAS, RUS-420029 Kazan
The ternary iron chalcogenides KFeS2 and RbFeSe2 consisting of chains of edge-sharing FeX4 (X = S, Se) tetrahedra have been investigated by means of magnetic susceptibility, specific heat, Mössbauer, and ESR measurements. The single crystals exhibit collinear antiferromagnetic (AFM) order with strongly reduced moments below 252 K and 248 K, respectively. For both compounds the small anomaly in C(T) and the corresponding low value of entropy at TN indicate a significant spin reduction and the existence of AFM fluctuations even far above TN. Mössbauer parameters determined in the entire temperature range indicate that iron in RbFeSe2 is in ferric (trivalent) state having strong covalent bonding to selenium ligands. The measured hyperfine field of 216 kOe at 4.2 K is quite reduced as compared to that in high-spin ferric compounds corroborating the strong spin reduction of Fe3+. The high-temperature susceptibility data of KFeS2 and RbFeSe2 suggest a one-dimensional metallic character along the chains.