Joseph Yahalom

Bio: Joseph Yahalom is an academic researcher from Technion – Israel Institute of Technology. The author has contributed to research in topics: Etching (microfabrication) & Corrosion. The author has an hindex of 15, co-authored 31 publications receiving 972 citations.

Anodizing of Pure Magnesium in KOH‐Aluminate Solutions under Sparking

Abstract: Anodizing of magnesium was studied in solutions containing 3 M KOH + 0.6 M KF + 0.21 M Na 3 PO 4 , with and without addition of 0.4 M and 1.1 M of aluminate. At constant applied current, the process occurs in two stages. First, the voltage rises linearly until an initial breakdown occurs. A thin and compact oxide film is formed at this stage. In the second stage an intense continuous spark is maintained on the metal surface. A thick oxide film is formed at the site of sparking. The formation of the film is accompanied by voltage oscillation and gas evolution. The anodic films formed under continuous breakdown conditions are rough and porous and enriched in aluminum. Anodic films formed in a bath containing 1.1 M aluminate at 15 mA/cm 2 are composed of a single oxide phase MgAl 2 O 4 spinel.

Formation of composition-modulated alloys by electrodeposition

Abstract: A method has been developed to produce composition-modulated alloys by electrodeposition. The method was demonstrated for the copper-nickel couple. Salts of the two component metals are dissolved in a common electrolyte and the potential is alternately pulsed for fixed durations between values above and below the reduction potential of the less noble component. Co-deposition of the nobler metal into the other metal layer is diminished by setting unfavourable diffusion conditions during the more cathodic pulse. Modulation was achieved down to 0.8 nm thick layers. The resulting composition-modulated alloys were analysed by Auger spectroscopy and X-ray diffraction.

Giant magnetoresistance in magnetic multilayered nanowires

Abstract: Giant magnetoresistance (GMR) is observed in a new type of nanostructured material consisting of magnetic multilayered nanowires formed by electrodeposition into nanometer-sized pores of a template polymer membrane. The composition of these nanowires is modulated over nanometer length scales with distinct magnetic and nonmagnetic metallic layers. Magnetoresistance measurements with the current perpendicular to the layers were performed on the array of parallel nanowires. GMR of about 15% was observed at room temperature on Co/Cu multilayered nanowires. (C) 1994 American Institute of Physics.

Multisegmented One‐Dimensional Nanorods Prepared by Hard‐Template Synthetic Methods

Abstract: In the science and engineering communities, the nanoscience revolution is intensifying. As many types of nanomaterials are becoming more reliably synthesized, they are being used for novel applications in all branches of nanoscience and nanotechnology. Since it is sometimes desirable for single nanomaterials to perform multiple functions simultaneously, multicomponent nanomaterials, such as core-shell, alloyed, and striped nanoparticles, are being more extensively researched. Nanoscientists hope to design multicomponent nanostructures and exploit their inherent multiple functionalities for use in many novel applications. This review highlights recent advances in the synthesis of multisegmented one-dimensional nanorods and nanowires with metal, semiconductor, polymer, molecular, and even gapped components. It also discusses the applications of these multicomponent nanomaterials in magnetism, self-assembly, electronics, biology, catalysis, and optics. Particular emphasis is placed on the new materials and devices achievable using these multicomponent, rather than single-component, nanowire structures.