Electrical and magnetic studies on promising Aurivillius intergrowth compound

Aurivillius intergrowth multiferroic phases are inspiring to many researchers owing to their scientific and technological application point of view. We have synthesized the intergrowth of promising three-layered Bi3.25La0.75Ti3O12 (BLT) and four-layered Bi4NdTi3Fe0.7Co0.3O15 (BNTF) compounds. The X-ray diffraction (XRD) data was analyzed by comparing our data with a standard eight-layered compound (Bi9Ti6FeO27) and the lattice parameters were evaluated. Showing a shoulder peak at maximum XRD intensity peak (1 1 8) is considered to be a signature of intergrowth formation. Scanning electron microscopic images have shown non-uniform disk-like grains with no preferential orientation. In order to extract information about relaxation species, Nyquist plots (Cole-Cole plots) were drawn at different temperatures. AC activation energies were evaluated from sigma(ac) vs. 1000/T plots, drawn at 10 kHz, 50 kHz and 100 kHz. Based on the impedance studies it is concluded that the hopping mechanism prefers through the doubly ionized oxygen atom vacancies and this phenomenon is corroborated to dielectric relaxation. Room temperature magnetic measurements display a weak ferromagnetic order. The intergrowth compound (BLT-BNTF) displayed ME coefficient (= 0.123 mV/cm-Oe) at lower magnetic fields. This is the most striking factor and helpful to fabricate room temperature Magnetoelectric sensors.

Automated summary

Aurivillius intergrowth multiferroic phases have attracted the interest of researchers due to their scientific and technological applications. In this study, the synthesis and characterization of the intergrowth compound Bi3.25La0.75Ti3O12 (BLT) and Bi4NdTi3Fe0.7Co0.3O15 (BNTF) were conducted. The results showed a signature of intergrowth formation, non-uniform grain morphology, and preferential hopping mechanism. The compound also exhibited weak ferromagnetic order and a high ME coefficient, making it potentially useful for room temperature magnetoelectric sensors.