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Structural and Magneto-Optical Properties of Co-doped ZnO Thin Films Prepared by Sol-Gel Method
| Content Provider | Semantic Scholar |
|---|---|
| Author | Neamţu, Johny Teodorescu, Cristian Mihail Georgescu, Gabriela Ferré, Jacques Mălăeru, T. Jitaru, Ioana |
| Copyright Year | 2008 |
| Abstract | Recent experiments evidenced room temperature ferromagnetism in ZnO:Co diluted magnetic semiconductors, however the diluted semiconductor nature and the ferromagnetism strongly depends on the preparation method employed. We have investigated the ability of the sol-gel route for the synthesis of cobalt doped ZnO films grown on Si (100) and glass substrates. A homogeneous and stable Zn 1-x CoxO sol was prepared by dissolving zinc nitrate hexahydrate and cobalt acetate tetrahydrate in a PVP (polyvinylpyrrolidone) solution, followed by annealing at 800 oC. Local structure studies of the Zn1-xCoxO thin films by XANE S (X -ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) proved the co-existence of a few amount of small metal cobalt aggregates with Co in non-stoichiometric ConOm aggregates, with n > m, and m ~ 4. Low temperature (1.5 K) Kerr magnetometry give a direct proof of a superparamagnetic behavior of the magnetic aggregates and allowed an estimate of the number of magnetically active atoms in Co aggregates, which is close to the number of Co excess atoms inferred from XANES and EXAFS considerations: n - m ~ 3 atoms per aggregate. To this main superparamagnetic phase, a weak ferromagnetic phase with coercitive field of ~ 200 Oe is superimposed, most probably due to metal cobalt nanoclusters. |
| Starting Page | 238 |
| Ending Page | 241 |
| Page Count | 4 |
| File Format | PDF HTM / HTML |
| Volume Number | 1 |
| Alternate Webpage(s) | https://briefs.techconnect.org/wp-content/volumes/Nanotech2008v1/pdf/307.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
