%0 Journal Article
%A Schmidt, Rainer
%A Basu, A.
%A Brinkman, A. W.
%A Klusek, Z.
%A Datta, P. K.
%T Electron-hopping modes in NiMn_(2)O_(4+δ) materials
%D 2005
%@ 0003-6951
%U https://hdl.handle.net/20.500.14352/51564
%X The resistance versus temperature (R–T) characteristics of NiMn_(2)O_(4+δ) thermistors have been analyzed. In the literature, electron transport in manganate spinels is commonly described by a small-polaron model for nearest neighbor hopping, but variable range hopping (VRH) has not been considered so far. In this study differentiated R–T data were analyzed, allowing a clear distinction between different modes of hopping. In pressed pellets and thick screen printed films conduction was well described by a VRH model for a parabolic density of states, which was confirmed by scanning tunneling spectroscopy.
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