TlFeX2 (X = S, Se) compounds crystallike as a chain structure in the form of long brittle filaments /1, 2 1 . Their monoclinic structure includes infinite chains (FeX2) built from FeX4 tetrahedra with mutual edges. Exchange interactions between the iron ions along the chain are realized by the chain of Fe-X-Fe configurations while within the FeX4 tetrahedron perpendicular to the chain directions they are realized by FE-X-T1-X-Fe configurations. Therefore one can assume that the strong difference between exchange interaction energies inside and between the chains leads to pseudo-one-dimensional magnetic structures of TlFeS2 and TlFeSe2.The aim of the present note is to investigate the influence of space-like and spin dimensions of the TlFeS2 and TlFeSe2 magnetic semiconductors on the behavior of heat capacity and magnetic susceptibility. The heat capacity (C ) is measured by the adiabatic method, and the magnetic susceptibility (x) by the Faraday method within the temperature range 4.2 to 300 K . The TlFeS2 and TlFeSe2 specimens were synthesized by reaction of the initial components in quartz ampoules / I / . Fig. l a and b show the results of heat capacity measurements of TlFeS2 and T1FeSe2. As is seen from the figures, a X anomaly characteristic of magnetic transitions is not detected in the C (T) dependence. W e could not find the corresponding isomorphic diamagnetic component in order to separate the lattice (Cht) and magnetic ( C ) contributions of the heat capacity for T1FeS2. As it is known, for this purpose Tarasov's model / 3 / o r its modified form / 4 , 51 is also used in the region Clat >> C which is suitable for describing the lattice heat capacity of layered and chain compounds using a smaller number of adjustable parameters. The analysis showed that the heat capacity of T1FeS2 from ;a200 to 80 K is well described by Tarasov's model for chain structures with el = 455 K and O3 = 91 K. At a200 K Cexp is about 2 % greater than Ctheor which is closer to the difference between C and Cv in this temperature range. Fig. l a also
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.