Effect of Low-Frequency Alternative-Current Magnetic Susceptibility in Ni80Fe20 Thin Films

• Main Authors: Yuan-Tsung Chen, S. H. Lin, Y. C. Lin
• Format: Article
• Language: English
• Published: Hindawi Limited 2012-01-01
• Series: Journal of Nanomaterials
• Online Access: http://dx.doi.org/10.1155/2012/186138

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 the χac of 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 maximum χac value with optimal resonance frequency (fres) increased spin sensitivity at optimal fres. The results obtained under the three conditions revealed that the maximum χac value and optimal fres of a 1000 Å-thick NiFe thin film are 3.45 Hz and 500 Hz, respectively, following postannealing at TA=250°C for 1 h. This suggests that a 1000 Å NiFe thin film post-annealed at TA=250°C is suitable for gauge sensor and transformer applications at low frequencies.