Magnetostrictive Theory And Composite Magnetostrictive Thick Film

In this thesis, the relationship of the film thickness and the deflection of the cantilever is studied systematically by free energy minimization. This work was initiative and systematic which provides the theoretical references to the cantilever design.At the same time, the magnetic hystere loop and the material extension according to the applied magnetic field were calculated by solving the equilibrium state equation M x Heff = 0. All these were done under the micromagntism when the effective fieldssuch as the exchanging coupling, magnetic anistropic, demagnetization and magnetostrictive field is included.In order to detect the micro deflection of the cantilever, the laser reflection optical level was adopted, thus generating laser dot displacement of several hundred folds is easy to be observed and measured. The position sensitive detector (PSD) was used to detect the amplified displacement signal, which was proceeded by a special circuit to get the voltage proportional to the displacement. The analogy voltage was converted to digital signal and collected by the enhanced parrelled port (EPP). The data collection software was written on the Windows9x platform. All the above were formed into the computer aided micro displacement detection system.Magnetostrictive thick films were made by screen printing and sintering techniques. The influnces of composition and sintering conditions (time and temperature) to the film topography, magnetic characters and magnetostriction were studied. The process conditions yielding to the best magnetostriction characters are obtained which are: temperature at 850 centigrade degree, time of 50 minutes and the ratio of Tefernol-D to galss being 1 to 0.6 in weight.