Monodispersed metal clusters in solid matrices: A new experimental setup

Abstract

We describe a new experimental setup for the production of samples of metal clusters embedded in matrices stable at ambient conditions. The cluster ions are generated in the gas phase and codeposited fragmentation-free together with the evaporated matrix. Mean cluster sizes range from a few to many thousands of atoms. For small clusters (n < 20) mass selection is possible, larger clusters are deposited in narrow size distributions. Matrix materials include metals (Cu, Ag) and oxides such as quartz. The performance of the apparatus as well as sample characterization procedures are described. We show first results on the magnetic properties of different cobalt cluster size distributions ( n = 15, 600, 2300, 6500) embedded in copper matrices, demonstrating inter-cluster as well as cluster-lattice interactions.

Interaction effects in dilute cluster-assembled magnetic nanostructures

“…The experimental setup is described in detail elsewhere 24 and is only sketched briefly. Cobalt cluster ions are generated in the gas phase using a homebuilt magnetron cluster source ͑based on the principle introduced by Haberland et al 25 ͒ and guided by ion optics through several differential pumping stages toward the deposition chamber.…”

“…We have previously used this technique for samples with higher concentrations 24 and observed a blocking temperature of ϳ50 K as well as a coercive field of Ͼ500 Oe for a sample of Co clusters with ͗n͘ = 15 atoms at a concentration of 8 at. % in a copper matrix.…”

Instability of Ag nanoparticles in SiO2at ambient conditions

“…The experimental setup has been described elsewhere [11] and will only be sketched briefly. Atomic or cluster ions are generated in the gas phase in a magnetron cluster source following the design of Haberland et al [13].…”

“…Recently it was shown that also very small silver clusters of a few atoms only have intriguing properties and that their fluorescence is not only an ideal tool for fundamental researchers to determine their atomic and electronic structure [8,9] but that it might also be exploited in applications [10]. The aim of our research is to find means to produce samples of well defined metal clusters stabilized in protective matrices and to study their properties [11,12]. In this article we present a series of feasibility studies on the generation of tailor-made samples of metal clusters embedded in co-evaporated silica matrices.…”

Spin-dependent transport in cluster-assembled nanostructures: influence of cluster size and matrix material

“…Samples are prepared according to the strategy of "clusterassembled materials" [12]. They consist of thin films of copper or silver in which are dispersed well-defined cobalt clusters.…”