Tailoring the multiferroic properties of BiFeO₃ by co‐doping Er at Bi site with aliovalent Nb, Mn and Mo at Fe site

Abstract

Single phase multiferroic undoped BiFeO 3 notoriously suffers due to the poor spincharge coupling resulting in limitations to device applications. The present work focuses on the tailoring of its multiferroic and magnetoelectric coupling properties by synthesizing multiferroic Bi 0.95 Er 0.05 Fe 0.98 TM 0.02 O 3 (TM = Nb, Mn and Mo) ceramics. The ferroelectric, magnetic, current leakage measurements and magnetoelectric effect were investigated. XRD along with the Reitveld refinement results confirms that all the samples possess perovskite based rhombohedral structure and reveals that doping of (Er, Nb), (Er, Mn) and (Er, Mo) induced the crystallographic distortion in the BFO lattice and hence induced a variation in the bond lengths and bond angle.Dual doping significantly enhanced the electrical, magnetic properties and magnetoelectric coupling as compared to BiFeO 3 . Doping has lowered the leakage current by three to four orders compared to BFO. The lattice distortion, reduced leakage current and destruction of spin-cycloidal structure could be the origin for these improved features. The (Er, Nb) doped BiFeO 3 yields enhanced ferroelectric character with the maximum polarization value of 0.46 µC/cm 2 , maximum ME coupling of 0.22 mV/ cm at a magnetic field of 130 G, an improved magnetization with a remanance value of 0.0903 emu/g and the lowest leakage current density. K E Y W O R D Sco-doped BiFeO 3 , current leakage density, magnetoelectric effect, multiferroic ceramics, Reitveld refinement, Spin-spiral structure

Magnetoelectrics: Three Centuries of Research Heading Towards the 4.0 Industrial Revolution

“…Lakshmi et al [ 31 ] synthesized multiferroic ceramic BiFeO 3 co-doped with aliovalent Nb, Mn and Mo at the Fe site by sol-gel [ 31 , 32 , 33 ]. Bi(NO 3 ) 3 ·5H 2 O, Fe(NO 3 ) 3 ·9H 2 O, Er(NO 3 ) 3 ·H 2 O, Nb 2 O 5 , Mn(NO 3 ) 2 ·H 2 O, MoO 6 were mixed in distilled water and stirred at 400 rpm until homogenization.…”

“…Then, the mixture was heated at 353.15 K on a hot plate until a gel was formed. The gel was converted into powders by auto-combustion, which was then ground and annealed at 873.15 K for 12 h. The pellets of 8 mm were prepared from the annealed powders by a hydraulic press under 6 tons pressure and sintered at 1073.15 K for 12 h [ 31 ]. The results of BiFeO 3 doped with Er and Nb showed a maximum ME coupling coefficient of 0.22 mV·cm −1 ·Oe −1 at 13 mT [ 31 ].…”

“…Lakshmi et al [31] synthesized multiferroic ceramic BiFeO 3 co-doped with aliovalent Nb, Mn and Mo at the Fe site by sol-gel [31][32][33] 6 were mixed in distilled water and stirred at 400 rpm until homogenization. Then, the mixture was heated at 353.15 K on a hot plate until a gel was formed.…”

“…Yang et al [36] developed single-phase multiferroic ceramics of (1 − x) BaTiO 3 − x BiFeO 3 (BT − x BFO) synthesized by solid-solution method that exhibited an ME coefficient of 0.87 mV•cm −1 •Oe −1 , providing a possibility of developing electrically or magnetically tunable thin-film devices. The reported single-phase ME materials, as well as their production technique are summarized in Figure 7, being observed that the ME voltage coefficient can assume a broad range of values, from less than (co-precipitation) [28] (PLD) [25] (PLD) [34] (Sol-gel) [20] (Sol-gel) [31] (Solid-state) [30] (Solid-state) [27] (Solid-state) [26] (Solid-state) [24] (Solid-state) [23] (Solid-state) [21] (Solid-state)…”

Magnetic materials for magnetoelectric coupling: An unexpected journey

“…Pellets of 8 mm are prepared from the annealed powders by a Hydraulic Pellet Press under six tons pressure and then sintered at 800°C for 12 hours (Divya Lakshmi and Shameem Banu, 2019).…”