Anisotropic magnetodielectric property of Bi4NdTi3Fe0.7Ni0.3O15 ceramics at room temperature

Bi₄NdTi₃Fe_0.7Ni_0.3O₁₅ (BNTFN) ceramics were fabricated via a modified solid-state reaction method. Comprehensive magnetodielectric (MD) characterization revealed significant anisotropy for MD coupling in BNTFN. In the high-frequency region, under identical frequency (f) and external magnetic field (H) conditions, MD coupling parallel to the c-axis (MD//) exhibited a weak positive effect, while that perpendicular to the c-axis (MD⊥) demonstrated a pronounced negative effect. When H < 5 kOe, MD// increased with H, whereas MD⊥ remained negligible. However, when H exceeded 5 kOe, MD// approached saturation, and MD⊥ began to rise progressively with further increases in H. Remarkably, at 1 MHz and under 10 kOe, MD⊥ was almost ten or twenty times stronger than MD// in BNTFN. More importantly, this work also elucidates the relationship between microstructure and MD coupling in four-layered perovskite compounds, offering valuable insights for designing high-sensitivity magnetocapacitance devices through strategic microstructure manipulation in layered oxide systems.