Description
Multiferroic composites have had a great emergence of recent popularity for their promising usage in electromagnetic coupling applications. By pairing ferroelectric and ferromagnetic phases together, the composite can directly convert magnetic fields to polarization or conversely transduce electric fields to magnetization. These composites have higher efficiency of magnetoelectric coupling than their conventional counterparts, and can perform at a wider range of temperatures than their single-phase multiferroic comparable. Herein, the focus will be on the converse magnetoelectric effect to produce magnetic flux from an applied voltage on a concentric ring structure. Our previous studies have reported on the effect of the electric field direction on these composites as well as the optimal location of magnetic flux measurement on the ring. This thesis will continue characterizing the converse magnetoelectric coupling of these concentric multiferroic composite rings by reporting on three factors of DC and AC magnetic field components. The first is to look at the effect of the DC magnetic field direction in otherwise optimal conditions with respect to a bias magnetic field sweep from 0 to 2625 Oe. Second, results report the magnetoelectric coupling coefficients components at the optimal measurement location, while measuring orthogonal to the optimal measurement direction. Third, the magnetoelectric coupling coefficient components are measured at the center of the ring. For the latter two results, the converse magnetoelectric behavior reported at electric fields from 20 to 80 V/mm applied at frequencies from 1 to 50 kHz, while bias magnetic fields from 0 to 2250 Oe are applied. It was found that the DC magnetic field direction did play a role in the behavior of the ring, such that the maximum measurement was at a 60° angle from the magnetic field. Additionally, the axial component exhibited a larger magnetoelectric coefficient than the opposing orthogonal component due to the demagnetizing field’s affinity towards the magnetocrystalline anisotropy. Furthermore, the inclusion of the composite ring had a notable magnetoelectric coupling at high magnetic fields due to magnetic shielding reducing the efficiency at lower magnetic fields.
