Effect of Poly‐Crystallinity on the Magnetoelectric Behavior of TiN/AlN/Ni MEMS Cantilevers Investigated by Finite Element Methods

Herein, magnetoelectric microelectromechanical system (MEMS) cantilevers are investigated on basis of a TiN/AlN/Ni laminate derived from experimental sensors using finite‐element simulations. With the anisotropic ΔE effect as an implication of the magnetocrystalline anisotropy, the lateral sensitivity of the sensor is studied for different nickel layer thicknesses and boundary conditions. It is found that above 60% of the cantilever length, the nickel is effectively not contributing to the sensor sensitivity anymore which is supported by the investigation of sensors with partial nickel coverage. The boundary condition of the magnetostrictive layer is found to affect the sensitivity of thick layers while it is negligible for thinning layers. Further investigations on basis of polycrystalline untextured nickel with slightly preferred orientations reveal a stronger effect on thin layers than on thicker ones. It is found to arise from relatively large crystals in the high‐sensitivity region near the clamping of the sensor. For thicker polycrystalline layers, the ΔE effect reproduces a characteristic based mainly on the (110) and (111) orientations while the (100) orientation appears to be underrepresented. The polycrystalline nature of experimental magnetoelectric MEMS sensors leads to different anisotropic contributions of individual grain orientations and aspects. As a consequence, the vibrational properties of MEMS sensors are affected resulting in a superposition of the individual anisotropic ΔE effects. Herein, sensors based on TiN/AlN/Ni cantilevers are investigated in regard of the ΔE effect and the derived sensitivity.