Effect of diamagnetic barium substitution on magnetic and photovoltaic properties in multiferroic BiFeO3

Abstract

Spontaneous magnetization and photovoltaic (PV) effects have been measured in (Bi 1-x Ba x)FeO 3-d ceramics for x ¼ 0.05, 0.10, and 0.15. The substitution of Ba 2þ ion in the A site of the perovskite unit cell can effectively enhance the ferromagnetic magnetization. The heterostructure of indium tin oxide (ITO) film/(Bi 1-x Ba x)FeO 3-d ceramic/Au film exhibits significant PV effects under illumination of k ¼ 405 nm. The PV responses decrease with increasing Ba concentration. The maximum power-conversion efficiency in the ITO/(Bi 0.95 Ba 0.5)FeO 2.95 /Au can reach 0.006%. A theoretical model based on optically excited current in the depletion region between ITO film and (Bi 1-x Ba x)FeO 3-d ceramics is used to describe the I-V characteristic, open-circuit voltage (V oc), and short-circuit current density (J sc) as a function of light intensity. V

Magnetization, phonon, and X-ray edge absorption in barium-doped BiFeO3 ceramics

“…A-site substitutions of rare-earth elements onto the BiFeO 3 perovskite cell have been employed to enhance ferromagnetic, ferroelectric, and photovoltaic responses [8][9][10][11]. A-site substitutions of alkaline earth metal elements in BiFeO 3 , i.e., (Bi 1-x A x ) FeO 3 (A = Ca, Sr, Ba), have also demonstrated an improvement of magnetic and ferroelectric properties [12][13][14][15][16][17][18][19][20][21][22][23]. It was proposed that magnetization can be enhanced as the doping ion radius increases due to suppression of the antiferromagnetic spiral spin configuration in BiFeO 3 [23].…”

Effect of Ba substitution on the multiferroic properties of BiFeO3 films on glass substrates

“…13 The enhancement of magnetic properties could be associated with distortion of the Fe-O-Fe bond angle due to Ba-doping, which directly affects the Fe-O-Fe exchanging pathway. [11][12][13][14][15][16]19 IV. CONCLUSIONS Structure, surface morphology, ferroelectric, and magnetic properties of Ba-doped BFO films prepared by pulsed laser deposition on Pt bottom electrodes with various t buffered glass substrates at low substrate temperatures of 450 C are reported.…”

“…Bi 1Àx Ba x FeO 3 targets (x ¼ 0.05, 0.1, and 0.15) were prepared by the solid state reaction method, and the detailed process was described elsewhere. 19 A substrate temperature of 450 C and an oxygen pressure of 50 mtorr were adopted with a laser repetition rate of 5 Hz. The composition of the film was identified by an energy dispersive x-ray analysis (EDX) and double checked by X-ray fluorescence (XRF) analysis.…”

“…8,9 For tailoring multiferroic properties, the substitution of different valence elements in BFO lattice was reported as an effective way. [10][11][12][13][14][15][16][17][18][19] The magnetization enhancement was found in A-doped BFO ceramics and films (A ¼ Ca, Sr, Pb, Ba, and La). [10][11][12][13][14][15][16][17] The saturation magnetization (M s ) was reported depending on the radius of the doping ion (r), i.e., the larger r, the higher M s .…”

Raman vibrations and photovoltaic conversion in rare earth doped (Bi0.93RE0.07)FeO3 (RE=Dy, Gd, Eu, Sm) ceramics

“…The Fe-O bond length (∼1.93 Å) in BFO is shorter than the Bi-O bond length (∼2.31 Å), thus the formation of V Bi is easier than formation of Fe vacancies [42]. The PV effects of (Ca, Sr, and Ba)-doped BFO ceramics with ITO and Au electrodes have shown strong dependences on ceramic thickness, light wavelength and intensity [43][44][45][46]. The PV open-circuit voltage and short-circuit current were described reasonably by a p-njunction-like model, which is based on optically excited charges in the interface between ITO film and doped BFO ceramics [43,46].…”