A Finite Element Analysis for Magnetostrictive Thin Film Structures and its Experimental Verification

초록

In this paper, a finite element formulation for magnetostrictive materials is reviewed first. Thereafter finite element code especially for micro-magnetostrictive actuators was developed. Two significant characteristics of the presented finite element code are: (1) the magnetostrictive hysteresis phenomenon is effectively taken into account, and (2) intrinsic geometric feature of typical thin film structures having large length to thickness ratio, which makes it very difficult to construct finite element mesh in the region of the thin film, is considered reasonably in modeling of micro- magneostrictive actuators. For verification purposes, magnetostrictive thin films were fabricated and tested in the form of a cantilevered actuator. The Tb-Fe film and Sm-Fe film are sputtered on the Si and Polyimide substrates individually. The magnetic and magnetostrictive properties of the sputtered magnetostrictive films are measured. The measured magnetostrictive coefficients are compared with the numerically calculated ones.