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Study of the local order around magnetic impurities in semiconductors for spintronics

Abstract : The semiconductors doped with magnetic ions (DMS) are promising materials for applications in the emerging field of spintronics. To address this challenge, a relatively high amount of magnetic impurities should enter the host crystal structure without phase separation, thus a detailed characterization at the nano-scale is mandatory. X-ray absorption fine structure spectroscopy is a technique well suited for probing the short-range order, so as to understand the underlying mechanisms responsible for the special physical properties of these materials. The starting point of this study is the well known GaAs doped with Mn where the creation of Mn interstitial defects reduce the ferromagnetic transition temperature (T_C) and post-growth treatments are necessary as a remedy. A new promising material is Fe-doped GaN showing interesting magnetic properties when doped around the solubility limit of Fe. In this case the key issue is the transition from Fe substitutional to the precipitation of Fe-rich nano-crystals at the conditions of spinodal decomposition. In fact, it is observed that T_C is considerably increased exploiting the spinodal decomposition as in the case of Mn in Ge, where Mn-rich ferromagnetic nanocolumns are formed in the crystalline host with a disordered local structure. Finally, first data are reported on the Mn incorporation in GaAs and InAs nanowires that are expected to play a key role in fabricating one dimensional DMS devices.
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https://tel.archives-ouvertes.fr/tel-00442852
Contributor : Mauro Rovezzi Connect in order to contact the contributor
Submitted on : Wednesday, December 23, 2009 - 10:20:32 AM
Last modification on : Friday, March 25, 2022 - 11:09:36 AM
Long-term archiving on: : Thursday, June 30, 2011 - 11:21:00 AM

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  • HAL Id : tel-00442852, version 1

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Mauro Rovezzi. Study of the local order around magnetic impurities in semiconductors for spintronics. Condensed Matter [cond-mat]. Université Joseph-Fourier - Grenoble I, 2009. English. ⟨tel-00442852⟩

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