ISSN:
1434-6036
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Abstract. Ion irradiation or heat treatments in vacuum of gel films prepared from mixtures of triethoxysilane with Fe and Ni nitrates permits to obtain a precipitation of metal particles in a glassy matrix, because these gels contain hydrido groups able to reduce Fe3 + and Ni2 + ions. The precipitation under irradiation is ascribed to the electronic excitations produced by the ions and the volume of metallic phase increases in proportion to the amount of energy transferred to electrons. The metal particles exhibit a narrower range of sizes than in films submitted to heat treatments in vacuum. Experiments of electron spin resonance indicate that the magnetic behavior of irradiated films is affected by a stress-induced anisotropy field. Films containing 3 to 7 at% Fe are in a superparamagnetic state in a given range of temperatures while the magnetic moments of nickel particles in films with similar metal contents exhibit a stronger correlation, due to a larger yield of precipitation and to the stress.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1140/epjb/e2004-00063-7
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