Magnetically anisotropic Co-Hf films for microdevices

What is it about?

Thin films of Co-Hf (≈ 86-14 % at.) were grown over Si micro-cantilevers using a glancing-angle deposition technique. A controlled easy direction of magnetisation (anisotropy field (μoHk ≈ 0.1 T) in the longitudinal or in the transverse direction of the micro-cantilevers was generated. The mechanical properties of the films under the action of a magnetic field were opposite depending on the magnetisation’s easy direction: i) their deflection was either zero or the maximum value depending on the direction of the applied magnetic field with respect to the parallel or transverse easy direction of magnetisation; ii) the shift in the resonance frequency under a longitudinal or transverse magnetic field was also different depending on the longitudinal or transverse easy direction of magnetisation. The use of these coated devices with micromagnet-like films for sensors and transducers is discussed.

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