Тип публикации: статья из журнала
Год издания: 2014
Идентификатор DOI: 10.1016/j.tsf.2013.12.029
Ключевые слова: Manganite-germanium, Solid state reaction, First phase, Mn5Ge3 alloy, Carbon impurity, Oxygen impurity, Annealing, Magnetic anisotropy, Carbon impurities, Diluted semiconductors, Electrical measurement, Homogeneous distribution, X-ray diffraction studies, Carbon, Curie temperature, Ferromagnetic materials, Ferromagnetism, Magnetization, Manganese, Oxygen, Phase separation, Photoelectron spectroscopy, Solid state reactions, Spinodal decomposition, X ray diffraction, Germanium
Аннотация: Solid state reactions between Ge and Mn films are systematically examined using X- ray diffraction, photoelectron spectroscopy, and magnetic and electrical measurements. The films have a nominal atomic ratio Ge: Mn = 20: 80 and are investigated at temperatures from 50 to 500 degrees C. It is established that after annealing at similar to 120 degrees C, the ferromagneticMn(5)Ge(3) phase is the first phase to form at the 20Ge/80Mn interface. As the annealing temperature increases to 300 degrees C, the weak magneticMn(5)Ge(2) + Mn3Ge phases simultaneously begin to grow and they become dominant at 400 degrees C. Increasing the annealing temperature to 500 degrees C leads to the formation of the ferromagnetic phase with a Curie temperature TC similar to 350- 360 K and magnetization 14- 25 kA/ m at room temperature. The X- ray diffraction study of the samples shows the reflections from the Mn5Ge3 phase, and the photoelectron spectra contain the oxygen and carbon peaks. The homogeneous distribution of oxygen and carbon over the sample thickness suggests that the increased Curie temperature and magnetization are related to the migration of C and O atoms into the Mn5Ge3 lattice and the formation of the Nowotny phase Mn5Ge3.xOy. The initiation temperature (similar to 120.) is the same in theMn(5)Ge(3) phasewith the solid- state reactions in the Ge/ Mn films as well as in the phase separation in the GexMn1 - x diluted semiconductors. Thus, we conclude that the synthesis of the Mn5Ge3 phase is the moving force for the spinodal decomposition of the GexMn1 - x diluted semiconductors. (C) 2013 Elsevier B. V. All rights reserved.
Журнал: THIN SOLID FILMS
Выпуск журнала: Vol. 552
Номера страниц: 86-91
ISSN журнала: 00406090
Место издания: LAUSANNE
Издатель: ELSEVIER SCIENCE SA
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