Magnetoelectric effect in three-layered gradient LiNbO3/Ni/Metglas composites

The effect of annealing in a permanent magnetic field on the magnitude of magnetoelectric coefficient in three-layered gradient magnetoelectric LiNbO₃/Ni/Metglas composites has been studied. A method of electrochemical nickel deposition on bidomain lithium niobate crystals has been demonstrated. We show that the optimum annealing temperature in a permanent magnetic field for the generation of the highest remanence in the Ni layer is 350 °C. The specimens annealed at this temperature exhibit the greatest shift of the magnetoelectric coefficient dependence on external magnetic field magnitude relative to the value H_dc = 0. The quasi-static magnetoelectric coefficient in the absence of an external magnetic field proves to be 1.2 V/(cm ∙ Oe). The highest magnetoelectric coefficient that has been achieved at a bending structure resonance frequency of 278 Hz proves to be 199.3 V/(cm ∙ Oe) without application of an external magnetic field. The experimental magnetoelectric coefficient figures for three-layered gradient LiNbO₃/Ni/Metglas composites are not inferior to those for most magnetoelectric composite materials reported earlier.