Preparation and characterization of electrodeposited CoWP magnetic thin films

Abstract

In recent years, one of the most interesting and widely investigated classes of materials has been magnetic alloy films. It has motivated to develop the microstructure thin films. The micro-fabrication technology for producing miniaturized components, systems and devices. Micro-electro-mechanical systems (MEMS) are being used in varieties of fields such as telecommunication, computers, aerospace, automobiles, biomedical, sensors, actuators and micro-optics, etc. Co and Co-rich hexagonal alloys on the other hand present high crystal anisotropy and potentially attractive hard magnetic properties in the deposited state. Cobalt based hard magnetic materials are commonly used in MEMS. It has high coercivity, low magnetic saturation, good corrosion resistance, low stress and high hardness has lead to the use of electrodeposited hard magnetic films in macroscopic and microscopic sensors, actuators and systems. The method of electrodeposition is large and growing in the electronics industry. This technique is interested due to miniaturization, cost competitiveness, easy maintenance and quality deposits. It provides an easy way to produce high quality films. In this thesis the preparation and properties of hard magnetic CoWP films were electrodeposited in presence of various phosphorous sources such as sodium hypophosphite (NaH2PO2) and phosphorous acid (H3PO3) and tri sodium citrate as complexing agent was studied. Surface and structural analysis were investigated by X-ray diffractometer (XRD) and scanning electron microscope (SEM). This thesis gives the optimized conditions of electrodeposition and the resultant properties of magnetic films with varying solution composition in presence of various phosphorus materials and organic additive. From these studies it was found that the bath with high concentration of urea and high concentration of NaH2PO2 was produced the film with high hard magnetic properties. newline