Giant magnetoimpedance effect of multilayered structure (F/SiO2)3/Ag/(SiO2/F)3 films deposited in a longitudinal magnetic field

Abstract

The soft magnetic properties and giant magnetoimpedance (GMI) effect of the multilayered structure (F/SiO2)3/Ag/(SiO2/F)3 (F≡Fe71.5Cu1Cr2.5V4Si12B9) films, which were prepared by radio frequency sputtering without and with a longitudinal magnetic field of about 72 kA/m, are studied. The results show that the GMI effect almost cannot be detected in the samples deposited without field, whereas, a longitudinal magnetic field applied during deposition process obviously optimizes the soft magnetic properties of the films, and noticeable GMI effect is obtained. The maximum values of the longitudinal and transverse GMI ratios are 45% and 44% at the frequency of 6.81 MHz, respectively. In addition, the dependence of magnetoimpedance ratio, magnetoresistance ratio, magnetoreactance ratio and effective permeability ratio on the frequency has been investigated. We found that the GMI spectrum curves in the longitudinal and transverse cases almost overlap for the field-deposited sample. The GMI effect is mainly a giant magnetoinductive effect at low frequencies. When f >9 MHz, magnetoreactance ratio changes to a negative, i.e., the property of reactance changes from inductive to capacitive.