Spin Manipulation in Co-Doped ZnO

Abstract:

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The magnetoresistance of n-type conducting, paramagnetic Co-doped ZnO films prepared by pulsed laser deposition on sapphire substrates has been studied experimentally and theoretically. Positive magnetoresistance (MR) of 124% has been observed in the film with the lowest electron concentration of 8.3·1017 cm−3, while only a negative MR of −1.9% was observed in the film with an electron concentration of 9.9·1019 cm−3 at 5 K. The positive MR is attributed to the quantum correction on the conductivity due to the s-d exchange interaction induced spin splitting of the conduction band. The negative MR is attributed to the magnetic field suppressed weak localization [1]. Voltage control of the electron concentration in Schottky diodes revealed a drastic change of the magnetoresistance and demonstrated the electrically controllable magnetotransport behavior in Co-doped ZnO [2]. The magnetically controllable spin polarization in Co-doped ZnO has been demonstrated at 5 K in magnetic tunnel junctions with Co-doped ZnO as a bottom electrode and Co as a top electrode [3]. There spin-polarized electrons were injected from Co-doped ZnO to a crystallized Al2O3 layer and tunnelled through an amorphous Al2O3 barrier. Our studies demonstrate the spin polarization and manipulation in Co-doped ZnO.

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Periodical:

Edited by:

Pietro VINCENZINI, Vojislav V. MITIC, Alois LOIDL and Dino FIORANI

Pages:

192-197

DOI:

10.4028/www.scientific.net/AST.67.192

Citation:

H. Schmidt "Spin Manipulation in Co-Doped ZnO", Advances in Science and Technology, Vol. 67, pp. 192-197, 2010

Online since:

October 2010

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