Multiferroic properties of polycrystalline Bi1−xCaxFeO3

Abstract

It is shown that Ca2+ doping at Bi-site results in the release of weak ferromagnetism in BiFeO3. Structural transformation from rhombohedral to triclinic is observed with 10% Ca doping. Raman measurements show the presence of oxygen vacancies with Ca doping and no evidence of either intermediate valence or the tetravalence of iron is observed from Mössbauer measurements. No significant change in Neel temperature is observed with Ca doping. The observed weak ferromagnetism and ferroelectric nature at room temperature indicates the multiferroic nature of Bi1−xCaxFeO3 (x=5% and 10%) samples.

Multiferroic properties of (Bi, Ca)FeO 3 films on glass substrates

“…All studied BCFO films exhibit small leakage, and thus good ferroelectric properties. This low leakage is the main reason why the present BCFO films show better ferroelectric properties as compared to those of BCFO ceramics [14,23]. In the BCFO films with x = 0.05, a relatively higher leakage current obtained for t = 10 nm might be correlated to the poor quality and slightly rougher film surface, and hence it might lead to a slightly rounder P-E loop with relatively inferior ferroelectric properties as shown in Fig.…”

“…Among the BFO ceramics with various substituents, Bi 1−x Ca x FeO 3 (BCFO) was reported showing interesting structural, magnetic, and electrical evolutions and a significant photovoltaic effect [15][16][17][18][19][20][21][22]. Moreover, a converse magnetoelectric effect was observed in BCFO ceramics [14], but very low electrical remanent polarization (2P r ) of 0.4-8 C/cm 2 hinders the applications [14,23]. Although the investigation on BCFO ceramics is extensive, the research on the multiferroic properties of BCFO polycrystalline films is relatively rare [24].…”

Room temperature ferromagnetic and ferroelectric properties of Bi1−xCaxMnO3 thin films

“…[19][20][21] No one has experimentally reported the studies of Bi 1-x Ca x MnO 3 (0 ≤ x ≤ 0.4) thin films and therefore it is of high interest and necessity to investigate the feasibility of enhanced room temperature magnetic and ferroelectric properties of BCMO (x < 0.5) films. In the present study, BCMO films have been grown at optimized growth conditions on n-type Si (100) substrate at two different temperatures and the magnetic, dielectric, elemental and ferroelectric properties of the BCMO films have been analysed.…”

Crystal structure and magnetic properties of Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba) multiferroics using neutron diffraction and Mossbauer spectroscopy

“…However, valance state of iron is same for both the spectra as hyperfine field for both sub spectra are typical for ferric ion. 20,21 These two sub spectra may be either due to the occupancy of iron at two different sites or due to the multiple valance state of iron or due to different ordering of magnetic moments. The neutron diffraction and XRD data refinement show that there is only one site for Fe ions.…”

“…The value of isomer shift and hyperfine field supports the presence of high spin Fe 3+ and rules out the possibility of mixed valance of iron. 21,22 The sextet corresponding to negative value of quadruple splitting corresponds to antiparallel ordering of magnetic moments which is responsible for antiferromagnetism and other sextet is due to the presence of weak ferromagnetism which arises due to the substitution of divalent and trivalent ions at A site. 23 Therefore, Mössbauer studies reveal that with divalent doping, no multiple oxidation state and occupancy of iron is observed.…”