Special features of the magnetic behaviour of the CuFeS2 semiconductor at low temperatures

Electronic Structure and Magnetic Properties of CuFeS2

“…The susceptibility curve obtained for sample 2 presents a small cusplike anomaly at a temperature of 50 K, suggesting the onset of an additional antiferromagnetic ordering. As mentioned in the Introduction, in some previously reported work ,, this unusual behavior has been attributed to the magnetic ordering of the copper ions below 50 K. However, in our case the cusplike anomaly is not observed for sample 1, and we suggest that this behavior may probably be associated with the presence of a small amount of paramagnetic impurities rather than with an onset of additional antiferromagnetic ordering. This interpretation is also consistent with the fact that this anomaly is not observed if the measurements are carried out in a 5000 Oe magnetic field (see Figure S2 in the Supporting Information for more details).…”

“…Apparently, as observed in the results obtained by Monte Carlo simulations, at the macroscopic level this small contribution would not have a significant effect on the magnetic susceptibility in the studied temperature range and it is only necessary to consider the iron spin network to obtain a good fit of the magnetic susceptibility curve. Although at lower temperatures our classical model is not appropriate to explain the magnetic behavior of CuFeS 2 , our experimental results seem to indicate that the anomalous magnetic behavior at ∼50 K reported in other works ,, may be more probably due to the presence of magnetic impurities than to a magnetic transition associated with the copper ions as suggested in the literature.…”

“…Magnetic exchange coupling constants are calculated through state-of-the-art first-principles DFT-based methods and then inserted in the CMC scheme to simulate the behavior of χ with temperature in CuFeS 2 . We also present new experimental magnetic susceptibility data for pure CuFeS 2 samples in order to compare with our theoretical results and to rule out the possibility of artifacts in the interpretation of earlier magnetic susceptibility measurements for natural samples of chalcopyrite due to the presence of magnetic impurities. ,− …”

Electronic Structure, Magnetism and Magnetocrystalline Anisotropy of Antiferromagnetic Semiconducting Chalcopyrite

“…They are semiconductors with a very broad bandgap distribution of 3.5 to 0.6 eV [6] and the optical band gap of CuFeS 2 was found to be 0.6 eV from optical absorption measurements [7]. The magnetic properties of CuFeS 2 have been intensively investigated in both theory and experiments [9,10,11,12].…”

“…and the Cu atoms on the 4a side are located at position (0, 0, 0). The Fe atoms on the 4b side are located at the position (0, 0, 1/2) and the S atoms on the 8d side are located at the position (0.257, 1/4, 1/8) [9]. Each atom of Cu and Fe is tetrahedrally coordinated by four S atoms, and each atom of S is coordinated by the two Cu and two Fe atoms.…”