A way to enhance the magnetic moment of multiferroic bismuth ferrite

Abstract

Transition metals, including Co, Cr, Ni and Mn, were doped into multiferroic Bi0.8La0.2Nb0.01Fe0.99O3 samples that were fabricated by a solid state reaction. X-ray diffraction results show that only the Mn-doped sample did not contain any impurity phases, while the other transition metal dopants destroyed the phase stability of the pure Bi0.8La0.2Nb0.01Fe0.99O3 phase and caused the formation of second phases. All the transition metal doped Bi0.8La0.2Nb0.01Fe0.99O3 samples show significant enhancement in their magnetic moment at room temperature in comparison with the BiFeO3 and Bi0.8La0.2Nb0.01Fe0.99O3 samples without transition metal doping. This is explained by the formation of local ferrimagnetic ordering or ferromagnetic ordering in the transition metal doped Bi0.8La0.2Nb0.01Fe0.99O3, according to the electron configurations of the dopant transition metal ions.

Fabrication, magnetic, and ferroelectric properties of multiferroic BiFeO3 hollow nanoparticles

“…It reveals that the BiFeO 3 hollow particles exhibit weak ferromagnetic behavior with magnetic moment of $0.07 emu/g at 5 K and 0.045 emu/g at 300 K in magnetic field of 0.1 T. The coercive field of sample is found to be 200 Oe at 5 K. These values are much larger than what has been observed in undoped bulk BiFeO 3 samples. 21 Since the grain size of BiFeO 3 forming the hollow particles is $40 nm, which is smaller than the period of the spin spiral structure (64 nm), enhanced magnetization is expected for the BiFeO 3 hollow particles due to uncompensated spins as a results of the broken period of the spiral spin structure. 13 Moreover, the defects, such as oxygen vacancies, can induce the formation of dangling bonds on the BiFeO 3 particle surface, which enhance the magnetic moments of these hollow particles.…”

Influences of ScTa co-substitution on the properties of Ultra-high temperature Bi3TiNbO9-based piezoelectric ceramics

“…However, the piezoactivity of pure BTNO ceramics is quite low (d 33 <7 pC/N) [10] for high temperature applications. The A-site substitution or/and B-site substitution have been shown to be effective in modifying the structure and polarization process [11][12][13][14][15][16][17][18][19][20][21][22][23]. Only a few works have addressed the properties of cation-modified BTNO-based ceramics.…”

Synthesis, microstructure and properties of BiFeO₃-based multiferroic materials: A review

“…However, the reasons for this lower conductivity of the doped material have been ascribed to different factors such as a decrease in the oxygen vacancies concentration or a possible niobium segregation at the grain boundaries. The case is that ferroelectric loops have Finally it has also been published that doping in B sites of the perovskite structure may lead to an enhancement in magnetization, since the substitution of iron atoms can increase the value of the Fe-O-Fe angle and, hence, modify the super-exchange interaction [165]. As reported, dopants like Ti 4+ [61,122,143,166], Nb 5+ [118,167] o Zr 4+ [168] can originate a weak ferromagnetism in BiFeO 3 materials.…”