| Autor: |
Jamet, Matthieu, Barski, André, Devillers, Thibaut, Poydenot, Valier, Dujardin, Romain, Bayle-Guillemaud, Pascale, Rothman, Johan, Bellet-Amalric, Edith, Marty, Alain, Cibert, Joël, Mattana, Richard, Tatarenko, Serge |
| Předmět: |
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| Zdroj: |
Nature Materials; Aug2006, Vol. 5 Issue 8, p653-659, 7p, 1 Color Photograph, 3 Graphs |
| Abstrakt: |
The emerging field of spintronics would be dramatically boosted if room-temperature ferromagnetism could be added to semiconductor nanostructures that are compatible with silicon technology. Here, we report a high-TC (>400K) ferromagnetic phase of (Ge,Mn) epitaxial layer. The manganese content is 6%, and careful structural and chemical analyses show that the Mn distribution is strongly inhomogeneous: we observe eutectoid growth of well-defined Mn-rich nanocolumns surrounded by a Mn-poor matrix. The average diameter of these nanocolumns is 3nm and their spacing is 10nm. Their composition is close to Ge2Mn, which corresponds to an unknown germanium-rich phase, and they have a uniaxially elongated diamond structure. Their Curie temperature is higher than 400K. Magnetotransport reveals a pronounced anomalous Hall effect up to room temperature. A giant positive magnetoresistance is measured from 7,000% at 30K to 200% at 300K and 9T, with no evidence of saturation. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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