The effects of competing magnetic interactions on the electronic transport and magnetic properties of CuCrS2 and CuCrSe2


  Girish C. Tewari  ,  Maarit Karppinen  ,  Ashok K. Rastogi  
Department of Chemistry, Aalto University, FI-00076 Aalto, Finland
Jawaharlal Nehru University, New Delhi 110067, India

We present a detail study of the electrical resistivity, thermoelectric power, magnetic susceptibility χ and the heat capacity CP in antiferromagnetic layered compounds CuCrS2 and CuCrSe2 at 2K-300K. CuCrS2 showed sharp cusp in χ and a lambda-like peak in CP at TN = 40K as expected for a 3D- magnetic order, while more metallic CuCrSe2 showed a rounded maximum in χ and the absence of sharp peak in CP around 55K, the CP at low temperature has T2–dependence in it which suggests 2D spin-liquid like excitation in its magnetic phase. We tentatively believe this behaviour 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.