Fe-B-Nb-Nd magnetic metallic glass thin film for MEMS and NEMS

Abstract

In MEMS/NEMS applications, it is always desirable to have materials with good mechanical properties such as high strength and corrosion resistance. Metallic glass thin films are known to exhibit such properties. Here we report on properties of magnetic metallic glass (Fe 0.72 B 0.24 Nb 0.04 ) (100-x) Nd x (4≤x≤8) thin films formed by electron cyclotron resonance (ECR) ion-beam sputtering. The atomic composition of the thin film is controllable by changing the number of (Fe 0.70 B 0.26 Nb 0.04 ) 80 Nd 20 ‘chips’ combined with a Fe 72 B 24 Nb 4 main target. The glass transition temperature (T g ), the crystallization temperature (T x ) and the supercooled liquid region (ΔT x ) are found to be 850 K, 946 K and 96 K, respectively. An atomically disordered structure was observed by X-ray diffraction, electron diffraction and high resolution transmission electron microscopy. The pristine thin film is found to be a soft magnetic material at room temperature. A 5 μm — thick cantilever was fabricated by using MEMS fabrication technology. We envision its use as a part of microelectric-power generator based on electromagnetic induction effect.