Enhanced magnetic, magnetodielectric, and field-dependent magnetoimpedance correlation in the Bi5Ti3FeO15/Bi2Fe4O9 composites

Abstract

The physical properties of the Aurivillius Bi5Ti3FeO15 compound are enhanced by adding the magnetic BFO compound. The magnetic, magnetodielectric (MD), and magnetoimpedance (MI) properties of Bi5Ti3FeO15/Bi2Fe4O9 composites are investigated. The samples are prepared by the sol–gel-modified method, and the Rietveld refinement verifies the diphasic nature of the composites. The Raman spectra demonstrate the shifting of the vibrational modes due to adding the BFO phase, which is associated with the BO6 (B = Fe/Ti) octahedral. The maximum shift in Raman modes and bond length of Fe-O is noticed for the x = 0.2 composite. Room temperature magnetization data reveals the highest value of Ms and Mr is found for x = 0.2 composite, which is caused by the interaction among the AFM/FM magnetic ordering. The frequency-dependent MD shows the maximum MD% strength of ∼0.55 % for x = 0.1 and minimum magnetoloss (ML)% of ∼0.08 % for x = 0.3 composites. Field variation of MD data shows ∼30 times enhancement of MD% and ∼7 times reduction of the ML% for x = 0.2 sample as compared to the pure sample. The enhanced MD effect is due to the non-collinear ordering of Fe spins in the BFO sample, which results in the possible inverse Dzyalonskii-Moriya interaction in the composites. Additionally, the Ginzburg-Landau approach confirms that the maximum coupling coefficient γ (6.79 emu−2. g2) is observed for x = 0.4 of the BFO sample. The field-dependent capacitive MI and Cole-Cole plot analysis reveals the capacitive origin behind the MD effect. The non-linear variance of magnetoconductance in the pure sample (x = 0.0) is attributed to the maximum ML%. Hence, the enhanced MD coupling with capacitive MI properties is a great advantage for designing magnetic sensors and storage devices.