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Study of magnetic and structural in CdGa2-2xCr2xSe4 materials

R. MASROUR1,2,* , M. HAMEDOUN1,3,4, A. BENYOUSSEF2,3,4, V. SAGREDO5, L. DE CHALBAUD5

Affiliation

  1. Laboratoire de Physique du Solide, Université Sidi Mohammed Ben Abdellah, Faculté des sciences Dhar Mahraz, BP 1796, Fes, Morocco.
  2. LMPHE,Faculté des Sciences, Université Mohamed V, Rabat, Morocco
  3. Académie Hassan II des Sciences et Techniques, Rabat, Morocco.
  4. Institute for Nanomaterials and Nanotechnologies, Rabat, Morocco
  5. Department of Physics, Faculty of Science, University de los Andes, Mérida, Venezuela

Abstract

The magnetic semiconductor CdGa2−2xCr2xSe4 systems with 0≤x≤1 have been grown by using the chemical vapour transport technical in a closed system. The transporting agent was CdCl2 in a proportion of 0.75 mg/cc of capsule. The starting material was previously synthesized. The structural characterization on the crystals was done by powder X-ray diffraction studies. The results show three different phases for various Cr concentration ranges: spinel structure for x ≥ 0.7 , rhombohedral for 0.5 ≤ x ≤ 0.6 and tetragonal for 0 ≤ x ≤ 0.4 . The temperature dependence of the magnetization suggests that the studied compound presents a ferromagnetic, the phase with complex spin arrangement induced by fluctuating exchange, the paramagnetic behavior and the spin-glass behaviour. The nearest neighbour J (x) 1 and the next-neighbour super-exchange J (x) 2 interactions are evaluated by using the mean field theory for the spinels CdGa2−2xCr2xSe4 systems in the range 0.8 ≤ x ≤ 1 . The magnetic exchange energy, the intraplanar and the interplanar interactions are deduced. The high-temperature series expansion (HTSE) combined with the Padé approximants method (PA) is applied to the spinels CdGa2−2xCr2xSe4 systems to determinate the magnetic phase diagrams, i.e. TC versus dilution x. The critical exponents associated with the magnetic susceptibility χ and with the correlation length ξ are deduced in the range 0.6≤x≤1..

Keywords

Magnetic semiconductor, X-ray diffraction, Exchange interactions, High-temperature series expansions, Padé approximants, Critical exponents.

Submitted at: Jan. 11, 2010
Accepted at: June 16, 2010

Citation

R. MASROUR, M. HAMEDOUN, A. BENYOUSSEF, V. SAGREDO, L. DE CHALBAUD, Study of magnetic and structural in CdGa2-2xCr2xSe4 materials, Journal of Optoelectronics and Advanced Materials Vol. 12, Iss. 6, pp. 1322-1326 (2010)