Effect of sputtering rate and ion irradiation on the microstructure and magnetic properties of Ni∕Si3N4 multilayers

Abstract

Relation between the optical properties of composite Si 3 N 4 thin films with embedded Cu clusters and the clusters morphology: IrradiationeffectsThe effect of postgrowth ion irradiation on the microstructure and the interface properties of amorphous carbon films on silicon In order to prepare Ni clusters embedded in amorphous Si 3 N 4 , Ni and Si 3 N 4 layers have been alternatively deposited using sputtering techniques. The nominal Ni layer thickness ranged from 2 to 60 Å and the number of layers was varied accordingly so as to keep the total amount of Ni constant. Extended x-ray-absorption fine-structure ͑EXAFS͒ spectroscopy has been used to study the Ni clustering as well as the isolated Ni ions in the silicon nitride matrix. For small Ni layer thickness, the Ni layer becomes discontinuous and the average size of Ni clusters can be determined. Aiming to modify the Ni surrounding, samples with the thinnest Ni layers have been irradiated with He and P. The EXAFS results show that the main effect is the removal of the isolated Ni in the Si 3 N 4 matrix. The size evolution of the Ni clusters depends on the type of the irradiating ion. A complete magnetic characterization is presented in order to correlate Ni surrounding with the magnetic properties of Ni clusters.

Effects of interparticle interactions in magneticFe/Si3N4granular systems

“…Additionally, we have used a model which relates the average coordination number ͑ACN͒ obtained by the EXAFS analysis with the bulk coordination number ͑CN bulk ͒ the microstructure ͑layer thickness and roughness͒ estimated by XRR, 28 FIG. 2.…”

“…Further details of the deposition process can be found elsewhere. 23,28 Several sets of samples, with constant silicon nitride layer thickness and variable iron thickness ͑t Fe from 5 to 0.7 nm͒ were prepared in order to study the formation of iron clusters. The number of bilayers ͑n͒ was increased to preserve a constant amount of Fe along the series.…”

Magnetic properties and short-range structure analysis of granular cobalt silicon nitride multilayers

“…For Ni/Si 3 N 4 , the presence of an interlayer formed by nickel nitride with a rock salt cubic geometry results in a diminution of the magnetic signal of the samples. 18 A reduction of the magnetization is also observed in the Fe systems, with the formation of a non-magnetic zinc-blende FeN phase. 19 However, in Mn/ Si 3 N 4 multilayers, it has been observed that the formation of a distorted manganese nitride phase induces a ferromagnetic signal in the samples.…”

Metallic nanoparticles detected by infrared spectroscopy

“…The Ag [1] clusters are made with a sequential deposition of Si 3 N 4 as spacer and Ag layers repeated 9 times. The Ni and Au clusters [3] are made with the same technique, the Ni thickness being different from one stack to the other. Each metallic layer is thin enough in order to form metal islands by a Volmer-Weber growth mechanism.…”