Conduction mechanisms and enhanced multiferroic properties of Sr doped Bi0.85−xPr0.15SrxFe0.97Mn0.03O3 thin films

Abstract

Pure BiFeO 3 (BFO) and Bi 0.85-x Pr 0.15 Sr x Fe 0.97 Mn 0.03 O 3 (BPS x FMO, x = 0.02-0.05) thin films were deposited on fluorine-doped SnO 2 (FTO/glass) substrates by a sol-gel method. The systematic studies of crystalline structure, surface morphologies, leakage conduction mechanisms, ferroelectric and magnetic properties of pure BiFeO 3 and Bi 0.85-x Pr 0.15 Sr x Fe 0.97 Mn 0.03 O 3 thin films were investigated. X-ray diffraction patterns, Rietveld analysis and Raman scattering spectra reveal that the (Pr, Sr and Mn) co-doped BiFeO 3 thin films give rise to a trigonal (R3m: R) structure transition with respect to the original rhombohedral structure of pure BiFeO 3 film. Fowler-Nordheim tunneling conduction mechanism dominates the leakage current of all the films in the relatively high electric field. The significantly enhanced ferroelectric properties of the Bi 0.85-x Pr 0.15 Sr x Fe 0.97 Mn 0.03 O 3 thin films were observed in comparison with pure BiFeO 3 film. In addition, the BPS 2 FMO film shows the enhanced ferromagnetism with the saturation magnetization (M s * 1.97 emu cm -3 ), which is almost three times larger than that of pure BFO film (M s * 0.67 emu cm -3 ), as a result of the small grain size effect and the collapse of space modulated spin structure by the structure transition.

Resistive Switching and the Local Electric Field in Bi0.85-xPr0.15RExFe0.97Mn0.03O3/CuFe2O4 (RE = Sr, Dy) Bilayered Thin Films

“…3−5 Several methods, such as optimizing the preparation techniques, 6−8 ion substitutions, 5,9−15 and the formation of composite, 16−19 have been applied to solve those deficiencies and to promote the practical application. But as the previous reports, 20,21 the discouraging ferromagnetism was obtained along with excellent ferroelectricity of the BFO films via ion substitution. Some studies 22−24 about the combinations of the ion substitutions and formation of heterostructure to improve the ferroelectricity and ferromagnetism simultaneously have been reported.…”

“…The coercive field ( H c ) are 610 Oe, 634 Oe, 754 Oe, and 725 Oe. On the basis of our previous works, ,, both the BFO and the ion-doped BFO thin films possess weak ferromagnetism. It means that the ferromagnetic properties of the bilayered thin films improved by comparison with BFO.…”

“…In this paper, we prepared bilayer thin films of Bi 0.85‑ x Pr 0.15 RE x Fe 0.97 Mn 0.03 O 3 /CuFe 2 O 4 (BP RE x FMO/CuFO, RE = Sr, Dy) based on the favorable results of our previous work. , The influence of Pr, Sr, Dy, and Mn doping the crystal, the leakage current density, and multiferroic properies of the thin films were investigated. We also studied the RS effects on the ion-doped BFO/CuFO ferroelectric semiconductor heterojunctions, which have not been studied hitherto in those thin films with metal–ferroelectric–semiconductor–metal structure.…”