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Low temperature ZnMnO by ALD

Aleksandra M. Wojcik 1Marek Godlewski 1,2Krzysztof Kopalko 1Elżbieta Guziewicz 1Rafał Jakieła 1Michal Kiecana 1Roman Minikayev 1Wojciech Paszkowicz 1Matti Putkonen 3,4Lauri Niinisto 4

1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
2. Cardinal Stefan Wyszynski University, College of Science, Warszawa, Poland
3. Beneq Oy, Ensimmainen Savu, Vantaa 01510, Finland
4. Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 Espoo, Helsinki, Finland

Abstract

Spintronics is one of the most promising directions of nano-electronics. To realize predicted devices we should master technology of ferromagnetic semiconductors, which is necessary step for high efficiency of injection of spin polarized carriers. Ferromagnetism (FM) above room temperature has been predicted for heavily doped p-type ZnMnO [1], which is thus considered as a promising material for spintronics. It has been found, however, that the often observed ferromagnetism of ZnMnO relates not to alloy properties, but to the presence of Mn precipitates in ZnMnO and also to the formation of foreign phase inclusions of various MnxOy oxides. These oxides show strong magnetic ordering as anti-, ferro-, and ferrimagnetic oxides are formed [2].

We used Atomic Layer Deposition (ALD) to grow ZnMnO films. Very low growth temperatures, from 160ºC up to 400ºC, were crucial to block formation of foreign phases. We used two types of Mn precursors: Mn(thd)3 and Mn(acac)3, and two types of Zn precursors, viz. zinc acetate (Zn(OAc)2) and diethyl zinc (DEZn). These films exhibit controlled magnetic properties. Properties of obtained materials will be discussed based on structural and magnetic investigations.

[1] T. Dietl, H. Ohno, and F. Matsukura, Science 287, 1019 (2000)

[2] C. Liu, F. Yun, H. Mokoc, J. Mater. Sci.: Mater. Electron. 16, 555 (2005).

Microchemistry F-120 ALE reactor was financed by Foundation for the Polish Science within the Sezam program.

 

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Related papers

Presentation: Invited at E-MRS Fall Meeting 2007, Symposium C, by Aleksandra M. Wojcik
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-10 13:55
Revised:   2009-06-07 00:44