Improving the properties of magnetic nano particles (Co_Ni) ferrite by pulsed laser deposition and study its biological effect.

Abstract

XI VSM Vibrating sample magnetometer MRI Magnetic resonance imaging FWHM Full width at half-maximum PXRD Powder X-ray diffraction GMR Giant magneto resistance PLD Pulse Laser Depostion MHA Mueller Hinton Agar RFA Radio frequency ablation MNPs Micronized nanoparticals MR Magmatic Recording MMONPs magnetic metal oxide nanoparticles . XIII ABSTRACT: In this research, we prepared magnetic nano particles in format Co1-xNix Fe2 O4 in two methods. The first method is Co-precipitationnand were used pulsed laser deposition (PLD). We used a mixture of nickel nitrate, cobalt nitrate, iron nitrate, as well as sodium hydroxide as a chelating agent to balance the ratio of the oxidizing agent. The ferrite NPs were calcined at temperatures (300 °C) for 3 hr. to remove water content and unwanted impurities and to obtain a better single-phase spinel structure. The resulting powder is then compressed into a disc with a diameter of (2 cm) and then we use laser deposition technology to obtain thin film. Structure and magnetic properties of the NPs were tested using XRD, FE-SEM, FTIR, and finally the Vibrating Sample Magnetometer (VSM), which revealed the presence of Super para magnetic samples. The x-ray spectrum shows that the pattern of the particles formed is of the face -centered cubic and the theoretical values of the lattice constant and crystalline size (D) were calculated .The crystalline size calculated was located in the range (22.6-26.6 nm), either in the pulsed laser deposition method in the range (13.7)nm, which reflects the highly crystalline nature of these nanoparticles. The FTIR spectrum shows two absorption bands ranging between 400 and 600 cm-1. These bands indicated that the composition of the spectrum for all the samples is ferrite. The Field emission scanning electron microscopes (FE-SEM) images confirmed that the preparation methods produced spherical nanoparticles with a slight change in the particle size distribution. The average particle size by coprecipitation had estimated to be about 23 nm and the average particle size by pulsed laser deposition(PLD) method had estimated to be about 20 nm. XIV The magnetic properties vibrating sample magnetometer (VSM) showed good correlation with the structural parameters of the spinal structure, which increased with the Ni content. When using nanoparticles prepared by co-precipitation method on Escherichia coli and Streptococcus bacteria, the highest inhibition zone ranged from (27-33) mm. When using nanoparticles prepared by using the method of pulsd laser deposition on the same types of bacteria, (S.aureus)was found to have the highest inhibition zone (22-32) mm , while Bacteria(Escherichia coli) the inhibition zone ( 27-30) mm.