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 mu V 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 T-2-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 T-N=55 K. (C) 2012 Elsevier Inc. All rights reserved.