Low Temperature Physics: 37, 83 (2011); https://doi.org/10.1063/1.3552132 (7 pages)
Физика Низких Температур: Том 37, Выпуск 1 (Январь 2011), c. 100-107    ( к оглавлению , назад )

Magnetic and superconducting properties of FeSe1–xTex (x 0, 0.5, and 1.0)

A.V. Fedorchenko1, G.E. Grechnev1, V.A. Desnenko1, A.S. Panfilov1, S.L. Gnatchenko1

V.V. Tsurkan2,3, J. Deisenhofer2, H.-A. Krug von Nidda2, A. Loidl2, D.A. Chareev4, O.S. Volkova5, and A.N. Vasiliev5

1 B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
E-mail: panfilov@ilt.kharkov.ua

2 Experimental Physics 5, Center for Electronic Correlations and Magnetism, Institute of Physics University of Augsburg, Augsburg 86159, Germany

3 Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028 Chisinau, Republic of Moldova

4 Institute of Experimental Mineralogy, Russian Academy of Sciences Chernogolovka, Moscow District 142432, Russia

5 Moscow State University, Physics Department, Moscow 119991, Russia

Received October 12, 2010

Аннотация

Magnetization studies for FeSe1–xTex (x 0, 0.5, and 1.0) compounds were carried out in magnetic fields up to 50 kOe and in the temperature range 2–300 K. The superconducting transition was observed at Tc 8 K and 13.6–14.2 K in FeSe0.963 and FeSe0.5Te0.5, respectively. For the most samples, a nonlinear behavior of the magnetization curves in the normal state gives evidence of a commonly observed substantial presence of ferromagnetic impurities in the compounds under study. By taking these impurity effects into account, the intrinsic magnetic susceptibility χ of FeSe0.963, FeSe0.5Te0.5, and FeTe was estimated to increase gradually with Te content. For FeTe a drastic drop in χ(T) with decreasing temperature was found at TN 70 K, which is presumably related to antiferromagnetic ordering. To shed light on the observed magnetic properties, ab initio calculations of the exchange enhanced magnetic susceptibility are performed for FeSe and FeTe within the local spin density approximation.

PACS: 74.70.Xa Pnictides and chalcogenides;
PACS: 74.20.Pq Electronic structure calculations;
PACS: 74.25.Ha Magnetic properties;
PACS: 75.30.Cr Saturation moments and magnetic susceptibilities.

Ключевые слова: FeSe, FeTe, high-temperature superconductivity, magnetization, electronic structure.