A Magentoelectric Coefficient Measurement System with a Free-Stress Sample Holder

Abstract

With less extra stress on the testing sample, a free-stress sample holder was designed to place the sample horizontally. With the free-stress sample holder, a magnetoelectric (ME) coefficient measurement system was developed based on dynamic method. This measurement system has the hardware part and the software part, integrated by the DC magnetic field generation module, the AC magnetic field generation module, the induced ME voltage detecting module and PC software module. Then, a sample of Terfenol-D/PZT/Terfenol-D trilayer was designed and fabricated, and the relationships of its ME coefficient influenced by the DC magnetic field and the frequency of the AC magnetic field were tested using the measurement system. And the results showed that the free-stress sample holder was proven to improve the accuracy of the measurement system by less stress interference.

Application of the Lock-In Technique in Magnetoelectric Coupling Measurements of the PZT/Terfenol-D Composite

“…At low DC fields (up to 0.14 T) there is a linear increase of U OUT relative to H DC . Next, the voltage reaches some maximum value and then gradually decreases between 0.34 and 0.45 T. The observed trend corresponds well to published data for PZT/Terfenol-D composites [13,22,23,25,29,30]. The shape of characteristics is related to the dependence of the magnetostrictive coefficient of Terfenol-D on the DC magnetic field, as shown in [22,29,31].…”

“…All peaks for various DC fields occur at approximately the same frequencies. In comparison to the data published for composites, in which the authors observe one or two separated peaks [12,13,22,23,[27][28][29][30], we detect multiple, overlapping resonant peaks (60-80 kHz range). The existence of resonant peaks shown in Figure 4 may be explained by the structure of the S1 composite.…”

“…Based on criteria such as frequency range, material constituents, and theoretical models found in the literature, it can be inferred that the resonance state observed in our study is due to bending and longitudinal modes. It should be pointed out that the number, nature, and frequency of resonant peaks also depend on mechanical boundary conditions (i.e., whether the sample ends are free or fixed) [22,26,30]. As may be observed from Figure 4, the values of magnetoelectric voltage of sample S1 depend on the external DC field.…”