کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1622259 1516400 2009 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Room temperature ferromagnetism in Mn-doped dilute ZnO semiconductor: An electronic structure study using X-ray photoemission
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
Room temperature ferromagnetism in Mn-doped dilute ZnO semiconductor: An electronic structure study using X-ray photoemission
چکیده انگلیسی

There are several confronting reports of room temperature ferromagnetic (FM) ordering in bulk as well as thin films of dilutely doped or even some undoped semiconductors. We have synthesized and characterized dilute Mn-doped (2 and 4%) ZnO pellets. SQUID measurements confirm that the 2% Mn sample shows the FM ordering above the room temperature and the FM contribution coming mainly from the bulk. However, the ordering gets completely quenched for 4% Mn doping. Upon cooling down, the 2% Mn-doped sample shows further enhancement in the magnetic properties while the 4% sample did not show any FM ordering down to 5 K. The powerful X-ray photoemission spectroscopy (XPS) was employed to compare the electronic structure of these two samples. The XPS results show that the manganese shifts toward the higher valence state upon Mn doping while there is no change in the zinc and oxygen valence. The atomic concentration of divalent Mn state is found to be dominant in the ferromagnetic sample. For the non-ferromagnetic sample, a larger contribution of higher oxidation Mn states is present that is correlated to the suppressed ferromagnetism. Interestingly, the oxygen content is also found to be higher in the 4% Mn sample than that in the 2% Mn sample that has been attributed to the charge neutrality of the samples. The present study provides evidence that the magnetization originates neither from any precipitating secondary phase nor from the oxygen content but the Mn2+ state plays a significant role for the FM properties in the Mn-doped ZnO system.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 477, Issues 1–2, 27 May 2009, Pages 379–385
نویسندگان
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