| Autor: |
Valenzuela, R., Ammar, S., Nowak, S., Vazquez, G. |
| Předmět: |
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| Zdroj: |
Journal of Superconductivity & Novel Magnetism; Oct2012, Vol. 25 Issue 7, p2389-2393, 5p, 1 Black and White Photograph, 5 Graphs |
| Abstrakt: |
The low field microwave absorption (LFMA at 9.5 GHz) properties of clusters of ZnNiFeO ferrite nanoparticles (NPs) consolidated by spark plasma sintering (PSP at temperatures in the 350-500 °C range) are analyzed. LFMA measurements were carried out at 77 and 300 K. The clusters, formed by ∼6 nm NPs, were first obtained by the forced hydrolysis in a polyol method from the corresponding metal acetates. It is found that the sign of LFMA, associated with the spin arrangement in the ferrite depends on the degree of consolidation. For monodispersed NPs, no change of sign is observed at low temperatures. For the as-produced clusters and the consolidated samples, a progressive change in the sign of the signal is observed as the sintering temperature is increased. This change of sign is associated with the occurrence of the triangular or canted Yafet-Kittel spin arrangement. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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