Novel Anisotropic Magnetoelectric Effect on δ-FeO(OH)/P(VDF-TrFE) Multiferroic Composites

The past decade has witnessed increased research effort on multiphase magnetoelectric (ME) composites. In this scope, this paper presents the application of novel materials for the development of anisotropic magnetoelectric sensors based on δ-FeO(OH)/P(VDF-TrFE) composites. The composite is able to precisely determine the amplitude and direction of the magnetic field. A new ME effect is reported in this study, as it emerges from the magnetic rotation of the δ-FeO(OH) nanosheets inside the piezoelectric P(VDF-TrFE) polymer matrix. δ-FeO(OH)/P(VDF-TrFE) composites with 1, 5, 10, and 20 δ-FeO(OH) filler weight percentage in three δ-FeO(OH) alignment states (random, transversal, and longitudinal) have been developed. Results have shown that the modulus of the piezoelectric response (10–24 pC·N–1) is stable at least up to three months, the shape and magnetization maximum value (3 emu·g–1) is dependent on δ-FeO(OH) content, and the obtained ME voltage coefficient, with a maximum of ∼0.4 mV·cm–1·Oe–1, is dependent on the incident magnetic field direction and intensity. In this way, the produced materials are suitable for innovative anisotropic sensor and actuator applications.