Magnetic properties of diluted magnetic semiconductors Pb1–yFeyTe
E.P. Skipetrov, A.A. Solovev,
Физический факультет Московского государственного университета им. М.В. Ломоносова Ленинские горы, 1, г. Москва, 119991, Россия
Химический факультет Московского государственного университета им. М.В. Ломоносова Ленинские горы, 1, г. Москва, 119991, Россия
I. Frantsevich Institute for Problems of Materials Science NAS str. Wilde, 5, Chernivtsi, 58001, Ukraine pos Анотація:
Received December 16, 2016
The phase and elemental composition and magnetic properties (B ≤ 7.5 T, 2.0 K ≤ T ≤ 70 K) of Pb1–yFeyTe alloys are studied at a variation of the impurity concentration along the single-crystal ingot synthesized by the Bridgman technique. The distribution of iron impurity along the length of the ingot in the main phase and the composition of microscopic inclusions of a second phase are determined. It is established that the magnetization of the samples contains several contributions: the paramagnetic one of the impurity ions, crystal lattice diamagnetism, contributions of free charge carriers, charge carriers in the impurity band, clusters of iron ions and an oscillating contribution of the de Haas–van Alphen effect. Consistent selection of these contributions is made. By approximation of magnetic field and temperature dependences of the contribution of the impurity ions by a sum of two terms based on the modified Brillouin functions, the nature of changes of the concentrations of iron ions in two different charge states along the ingot are determined. It is shown that the charge carrier concentration, defined by the de Haas–van Alphen oscillations, are in satisfactory agreement with the Hall concentration, indicating a weak influence of inclusions of a second phase and magnetic clusters on homogeneity and physical prop-erties of the main phase in Pb1–yFeyTe alloys.
PACS: 71.20.Nr Semiconductor compounds; PACS: 71.55.–i Impurity and defect levels; PACS: 75.50.Pp Magnetic semiconductors.
Key words: PbTe-based alloys, 3d-transition metal impurities, electronic structure, magnetic impurity ions, magnetic field and temperature dependences of magnetization, modified Brillouin function.