Anisotropic magnetic and electrical properties in textured single phase multiferroic Bi_4.5Sm_0.5Ti₃Fe_0.8Cr_0.2O₁₅ ceramics

Here we report the synthesis of single-phase Cr and Sm doped Aurivillius Bi₅Ti₃FeO₁₅ (SBTFO) ceramics using conventional solid-state route method. The prepared composition exhibits the anticipated four-layered Aurivillius structure having an orthorhombic crystal structure and A2₁am space group, as confirmed by the XRD in conjunction with the Rietveld refinement. Additionally, the doping-induced crystallite size and strain were analyzed using a Williamson Hall plot, whereas cross-sectional FESEM revealed the plate-like structure having an average crystallite size of 0.5 μm. The SBTFO ceramics demonstrate exemplary ferroelectric and ferromagnetic properties with remnant polarization (2P_r) and remnant magnetization (2M_r) of 0.96 μC/cm² and 0.06 emug⁻¹, respectively. The temperature and frequency dependence of dielectric study reveals a Maxwell-Wagner relaxation with a higher loss in a low frequency regime perhaps due to leakage current in the system. The frequency dependent AC conductivity investigation adheres to Jonscher's formulation, indicating that the long-range hopping mechanism governs the conduction process, with an activation energy of 0.56 eV. Non-Debye type relaxation mechanism coupled with negative temperature coefficient of resistance (NTCR) behavior was specified by temperature dependent impedance spectroscopy, whereas the modulus spectroscopy revealed the multiple relaxation phenomena. Furthermore, the impedance and modulus processes computed activation energy of 0.74 eV and 0.32 eV, respectively, indicate the involvement of distinct charge carriers in the relaxation and conduction processes. The present work illustrates a versatile approach for designing high-performance, room-temperature multiferroic materials, demonstrating their potential for next-generation industrial applications, including non-volatile memory, spintronic devices, and multifunctional sensors.