Effects of competing magnetic interactions on the electronic transport properties of CuCrSe2

We have synthesized single-phase samples of the CuCrSe2 phase that exhibits hexagonal-rhombohedral layered crystal structure with space group R3m. Here we present a detailed study of electronic transport and magnetic properties of CuCrSe2. We moreover investigate the heat capacity of CuCrSe2 in comparison to that of CuCrS2. The electrical resistivity of CuCrSe2 shows metallic-like behavior down to 2 K, while the thermoelectric power is large around 100 μV K−1 at 300 K. A weak anomaly in resistivity and a rounded maximum in magnetic susceptibility are observed around 55 K. No sharp transition at 55 K is observed in the heat capacity of CuCrSe2, rather a visible maximum is seen. At low temperatures from 2 to 14 K, the magnetic heat capacity follows T2-dependence. We tentatively believe this behavior of CuCrSe2 to be due to competing magnetic interactions between intralayer Cr atoms. The ferromagnetic Cr–Se–Cr indirect exchange among intralayer Cr atoms is enhanced in the selenide compound (that is more metallic than the sulfide compound), and competes with the antiferromagnetic Cr–Cr direct interactions. The interlayer antiferromagnetic exchange through Cu atoms leads to magnetic ordering at low temperature at TN=55 K.

Comparison of magnetic properties of CuCrSe2 and CuCrS2 indicates a sharp cusp-like anomaly in magnetic susceptibility at the antiferromagnetic transition of CuCrS2 while the maximum of CuCrSe2 is well rounded. Magnetization is reversible after field-cooling (FC) and zero-field-cooling (ZFC) for both compounds.Figure optionsDownload as PowerPoint slideHighlights
► Layered CuCrSe2 can be synthesized in both fully and partially cation-ordered forms.
► Contrary to previously believed insulating nature the cation-ordered phase is metallic.
► Magnetic property of CuCrSe2 is somewhat different from that of CuCrS2.
► Magnetization and heat capacity data suggest complex short-range ordering for CuCrSe2.