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Multiferroic composite materials operating under the principle of strain mediation across the interfaces separating different material boundaries address many limitations of single-phase magnetoelectric materials. Although significant research has been conducted to explore their responses relating to the topography and directionality of material polarization and magnetic loading, there remain unanswered questions regarding the long-term performance of these multiferroic structures. In this study, a multiferroic composite structure consisting of an inner Terfenol-D magnetostrictive cylinder and an outer lead zirconate titanate (PZT) piezoelectric cylinder was investigated. The composite was loaded over a 45-day period with an AC electric field (20 kV/m) at a near-resonant frequency (32.5 kHz) and a simultaneously applied DC magnetic field of 500 Oe. The long-term magnetoelectric and thermal responses were continuously monitored, and an extensive micrographic analysis of pretest and post-test states was performed using scanning electron microscopy (SEM). The extended characterization revealed a significant degradation of ≈30–50% of the magnetoelectric response, whereas SEM micrographs indicated a reduction in the bonding interface quality. The increase in temperature at the onset of loading was associated with the induced oscillatory piezoelectric strain and accounted for 28% of the strain energy loss over nearly one hour.

Magnetoelectricity in bulk strain‐mediated multiferroic composites has been growing in attention for sensor and actuator applications. For actuator applications, where electric to magnetic coupling is utilized, the magnetoelectric composite alters the magnetic field which it is within resulting in full‐field spatial and directional changes to the magnetic flux. To grasp a better understanding of the full‐field magnetic behavior of a magnetoelectric composite with a complex geometry, multiple magnetic flux measurements in different locations and directions are taken to unveil interesting behaviors and phenomena such as modality and postfabrication material property modification. Remarkably, a significant multidirectional magnetic flux is measured at a distance away from the composite which can be harnessed to improve the efficiency of multiferroic actuators. In addition, the intensity and directionality of the magnetic flux is highly tunable by modifying the frequency and bias magnetic field depending on the need for the application.