Effect of Low-Frequency Alternative-Current Magnetic Susceptibility inNi80Fe20Thin Films

Abstract

X-ray diffraction (XRD) results indicate that the NiFe thin films had a face-centered cubic (FCC) structure. Post-annealing treatment increased the crystallinity of NiFe films over those at room temperature (RT), suggesting that NiFe crystallization yields FCC (111) texturing. Post-annealing treatments increase crystallinity over that obtained at RT. This paper focuses on the maximum alternative-current magnetic susceptibility(χac)value of NiFe thin films with resonance frequency(fres)at low frequencies from 10 Hz to 25000 Hz. These results demonstrate that theχacof NiFe thin films increased with post-annealing treatment and increasing thickness. The NiFe (111) texture suggests that the relationship between magneto-crystalline anisotropy and the maximumχacvalue with optimal resonance frequency(fres)increased spin sensitivity at optimalfres. The results obtained under the three conditions revealed that the maximumχacvalue and optimalfresof a 1000 Å-thick NiFe thin film are 3.45 Hz and 500 Hz, respectively, following postannealing atTA=250°C for 1 h. This suggests that a 1000 Å NiFe thin film post-annealed atTA=250°C is suitable for gauge sensor and transformer applications at low frequencies.