Anisotropic magnetodielectric property of Bi₄NdTi₃Fe_0.7Ni_0.3O₁₅ ceramics at room temperature

Abstract Bi 4 NdTi 3 Fe 0.7 Ni 0.3 O 15 (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.