Search

The roles of applied magnetic field during the current annealing of Co 68.15 Fe 4.35 Si 12.5 B 15 soft magnetic amorphous ribbons are studied. Samples heat treated by Joule heating effect in open air and simultaneously in the present of longitudinal external magnetic field showed asymmetric magnetoimpedance (AMI) behavior. The AMI profile can be related to the exchange bias interaction between the soft magnetic amorphous material and a harder magnetic crystalline phase formed on the surface of the ribbon. This effect stems from thermal effect, the transverse Oe field generated from the annealing current which is thickness dependent and the longitudinal external field. The single peak AMI with the field sensitivity of 101%/Oe for DC annealing current is achieved. Our results could address a simple way to achieve the AMI response toward developing high sensitive magnetic field sensors. [ABSTRACT FROM AUTHOR]

The magnetic anisotropy field distribution is discussed for Co‐based amorphous ribbon annealed under different field conditions leading to different induced anisotropies: longitudinal field (LF) and transversal field (TF) annealing. In order to understand the relation between the field annealing‐induced anisotropy and the performance of meander‐core orthogonal fluxgate sensor, field‐annealed ribbons with different in‐plane anisotropies as cores of orthogonal fluxgate sensors are employed and both noise and sensitivity in fundamental mode are measured. Experimental results indicate that LF annealing‐induced anisotropy with easy axis perpendicular to the direction of excitation field can effectively improve the sensor sensitivity. On the other hand, TF annealing‐induced anisotropy with easy axis parallel to excitation field results in lower sensitivity, but the noise is also lower. The results obtained are useful for developing the high‐performance orthogonal fluxgate sensors based on amorphous ribbon cores. This paper studies the magnetic anisotropy field distribution for Co‐based amorphous ribbon annealed under longitudinal field (LF) and transverse field (TF). Furthermore, the influences of field annealing‐induced magnetic anisotropy on the performance of meander‐core orthogonal fluxgate sensors are investigated. It is an interesting work which is important in the performance improvement of magnetic sensors based on amorphous materials. [ABSTRACT FROM AUTHOR]