Effect of Coating and Annealing on Giant Magneto Impedance in Co and Fe-Based Amorphous Wires

Abstract

Effect of coating with different chemical complexes on giant magneto impedance effect (GMI) was experimentally investigated in Fe and Co-based amorphous wires. The successive ionic layer adsorption and reaction (SILAR) technique was used for coating of the samples at room temperature. The SILAR method mainly based on adsorption and reaction on the ions from the solution and rinsing. Co and Fe-based amorphous wires were coated with CoO, asphaltene and ZnO chemical complexes. The coating thickness was determined to be about 1 μm thick. Maximum GMI ratio for Co and Fe-based samples were measured at 4 MHz and 5 MHz frequency, respectively. Influence of annealing at different temperatures on GMI effect was also experimentally investigated in the same samples. The coated samples were annealed at 300 C, 400 C, 500 C and 600 C temperatures in order to stress relief for 30 minutes. It is observed that the GMI ratio on Co- and Fe-based ZnO coated samples was highest at 500 ºC, while it was maximum on CoO coated Co-based samples at 400 ºC and on CoO coated Fe-based samples at 500 ºC. The highest GMI ratio among the measured samples was detected as 216 on the Fe-based, ZnO coated and annealed sample at 500 ºC at 5 MHz, while the smallest GMI ratio, was found to be as 88 on Co-based as-cast sample at 4 MHz. The measurements show that the GMI ratio is a combined effect of coating, annealing and frequency of ac current in a static magnetic field. Keywords Amorphous magnetic materials, SILAR technique, giant magneto impedance. Special Issue of Educational Sciences DOI: 10.7176/JSTR/6-06-03