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Carbon diffusion and reactivity in Mn5Ge3 thin films.

Authors :: Petit, Matthieu
Dau, Minh Tuan
Monier, Guillaume
Michez, Lisa
Barre, Xavier
Spiesser, Aurelie
Thanh, Vinh Le
Glachant, Alain
Coudreau, Cyril
Bideux, Luc
Robert-Goumet, Christine
Source :: Physica Status Solidi (C); Jun2012, Vol. 9 Issue 6, p1374-1377, 4p
Publication Year :: 2012
Abstract: The Curie temperature of Mn<subscript>5</subscript>Ge<subscript>3</subscript> has been successfully enhanced by carbon doping. In this context the diffusion of a carbon thin film in Mn<subscript>5</subscript>Ge<subscript>3</subscript> has been studied at room temperature. A value of the diffusivity of about D = 2.4 × 10<superscript>-23</superscript> ± 0.5 × 10<superscript>-23</superscript> m<superscript>2</superscript> s<superscript>-1</superscript> is reported. This value is in the typical range of interstitial diffusion coefficients. Moreover Auger Ge and Mn peaks shifts and Ge<subscript>3d</subscript> core level have been investigated to get some details on the reactivity of carbon atoms in Mn<subscript>5</subscript>Ge<subscript>3</subscript>. Mn Auger transitions display a shift of 4 eV whereas Ge transitions do not. Similarly Ge<subscript>3d</subscript> core level does not contain C related contribution but presents a Mn one. These observations confirmed the fact that carbon atoms are not inert species for Mn. It suggests that a ternary Ge-Mn-C alloy could occur and should be taken into account when doping the Mn<subscript>5</subscript>Ge<subscript>3</subscript> with carbon. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]