Photoemission study of Eu 2+/3+ ions in ferromagnetic (Eu,Gd)Te semiconductor layers

• Autorzy: Dziawa P. , Orłowski B. A. , Osinniy V. , Pietrzyk M. , Taliashvili B. , Story T. , Johnson R. L.
• Konferencja: Conference New Materials for Magnetoelectronics, Będlewo, 3-6 May 2006
• Języki publikacji: EN

Abstrakty

EN

(Eu,Gd)Te ferromagnetic semiconductor layers grown by molecular beam epitaxy technique on BaF2 (111) monocrystalline substrates were investigated by resonant photoemission spectroscopy using synchrotron radiation. In n-(Eu,Gd)Te layers, a ferromagnetic transition induced by electron concentration is observed. Magnetic as well as electrical properties of this material depend strongly on the charge state (2+ vs. 3+) of Eu and Gd ions known to be sensitive to crystal stoichiometry and formation of oxide complexes. The relative concentration of Eu2+ and Eu3+ ions was determined from the analysis of the resonant photoemission energy distribution curves (EDC), measured at photon energies close to 4d-4f resonance. After various in-situ annealing and Ar sputtering procedures, a clear improvement of crystal stoichiometry of (Eu,Gd)Te layers was observed as manifested by the increase of Eu2+ intensity in the spectra. Contribution of Eu 4f shell to the total density of states was also analyzed and found at the valence band edge for Eu2+ ions and about 6 eV lower for Eu3+ ions.

Słowa kluczowe

EN

spintronics; ferromagnetic semiconductor; rare earth compound; photoemission

• Wydawca: De Gruyter
• Czasopismo: Materials Science Poland
• Rocznik: 2007
• Tom: Vol. 25, No. 2
• Strony: 377--382
• Opis fizyczny: Bibliogr. 7 poz.

Twórcy

autor

Dziawa P.

autor

Orłowski B. A.

autor

Osinniy V.

autor

Pietrzyk M.

autor

Taliashvili B.

autor

Story T.

autor

Johnson R. L.

• Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland

Bibliografia

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