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The strongly enhanced room temperature ferromagnetism in Bi0.5Na0.5TiO3 materials was obtained via modification of YMnO3 as solid solutions. The weak ferromagnetism in pure Bi0.5Na0.5TiO3 was changed to ferromagnetism and antiferromagnetic-like with increasing the concentration of YMnO3 addition. The maxima magnetic moment was estimated at around 28.4 memu/g for 9 mol.% YMnO3-modified Bi0.5Na0.5TiO3 as a solid solution. The reduction of the optical bandgap energy from 3.18 eV to 2.01 eV was obtained via increasing YMnO3 addition into host Bi0.5Na0.5TiO3 crystal as solid solutions with amounts up to 9 mol.%. We suggested that the observation in the reduction of optical bandgap energy and great enhancement of the magnetic moment in YMnO3-modified Bi0.5Na0.5TiO3 compounds were strongly related to the random distribution of Y and Mn cations into the host lattice of Bi0.5Na0.5TiO3 crystals. We expected that our work will provide a simple way to integrate room temperature ferromagnetism into currently developed green ferroelectric materials. [ABSTRACT FROM AUTHOR]

The Ni 1 − x CoxTiO3 (0 ≤ x ≤ 1) solid solution powders were prepared by an aqueous sol–gel method. The structural, optical, magnetic and ferroelectric properties of NiTiO3 were investigated by X-ray diffraction, scanning electron microscope, UV–Vis absorption, vibration samples magnetometer and ferroelectric test system. The X-ray diffraction analysis revealed that prepared materials were in a single phase with rhombohedral structure with x up to 1. The increasing Co content resulted in decreasing of tolerance factor and increasing of the lattice constant. The crystalline size increased with an increase of Co content. The optical bandgap value of solid solution increased from 2.23 eV for NiTiO3 to 2.36 eV for CoTiO3. The magnetic hysteresis loop results indicate that all samples showed paramagnetic state at room temperature. A correlation between magnetization values and composition of the materials was observed with magnetization values which increased with increasing of CoTiO3 content in solid solution. Ferroelectric polarization analysis showed that the polarization of the Ni 1 − x CoxTiO3 solid solution depended on x value and reached the maximum with x = 0. 4. [ABSTRACT FROM AUTHOR]

Er½Na½TiO3–Bi½Na½TiO3 solid solutions were prepared by a sol–gel technique. The complex distortion of the rhombohedral structure of host Bi½Na½TiO3 compounds was obtained caused by the addition of the solid solution of Er½Na½TiO3 into the host Bi½Na½TiO3 matrix. The random incorporation of Er3+ cations into the host crystal of the Bi½Na½TiO3 material resulted in reducing its optical band gap from 3.04 to 2.79 eV by increasing the Er½Na½TiO3 amount. The strong green emission at 550 nm was obtained at room temperature and is related to the emission of Er3+ cations from 4S3/2 to 4I15/2 levels. The observation of strong photoemissions at room temperature of Er½Na½TiO3-Bi½Na½TiO3 binary system promises to create the next generation of smart electronic devices. [ABSTRACT FROM AUTHOR]

In this report, solid solutions of (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ materials were synthesized by a chemical method. X-ray diffraction and Raman scattering were used to study the structural properties of the (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ solid solutions. All studied samples had rhombohedral symmetry, where the Sr and Ni cations tended to randomly incorporate with the host Bi1/2Na1/2TiO3 lattices during the formation of solid solutions. The random incorporation of Sr and Ni cations into the host lattices resulted in structural distortion and reduced the optical band gap from 3.04 eV for the pure Bi1/2Na1/2TiO3 to 2.63 eV for the 9 mol.% SrNiO3-δ-modified Bi1/2Na1/2TiO3 sample. The complex magnetic properties of (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ system were investigated as a function of SrNiO3-δ concentrations. We expected that our simple and flexible method could be used to integrate the ferromagnetic properties in current advanced functional lead-free materials. [ABSTRACT FROM AUTHOR]

New solid solution (1−x)Bi1/2Na1/2TiO3+xBaNiO3−δ materials were synthesized by a chemical method. The X-ray diffraction and Raman scattering structure studies confirmed that the BaNiO3−δ materials were well soluted in the host Bi1/2Na1/2TiO3 materials. The random incorporation of Ba and Ni into the host Bi1/2Na1/2TiO3 materials was displayed by the optical properties where the optical bandgap values were reduced, and the photoluminescence was suppressed. The complex magnetic properties of Bi1/2Na1/2TiO3 materials were obtained as a function of BaNiO3−δ amounts in the solid solutions. The role of co-modification of A- and B-sites via alkaline earth metals and transition metals as substitution and interstitially on magnetic properties of Bi1/2Na1/2TiO3 materials was experimentally proposed, which is further supported by first-principles density functional theory calculations. We expected that our work provided a new method to inject the ferromagnetic properties in lead-free ferroelectric materials for smart electronic applications. [ABSTRACT FROM AUTHOR]

New solid solution of Na0.5Bi0.5TiO3 with BaFeO3−δ materials were fabricated by sol–gel method. Analysis of X-ray diffraction patterns indicated that BaFeO3−δ materials existed as a well solid solution and resulted in distortion the structure of host Na0.5Bi0.5TiO3 materials. The randomly incorporated Fe and Ba cations in the host Na0.5Bi0.5TiO3 crystal decreased the optical band gap from 3.11 to 2.48 eV, and induced the room-temperature ferromagnetism. Our density-functional theory calculations further suggested that both Ba for Bi/Na-site and Fe dopant, regardless of the substitutional sites, in Na0.5Bi0.5TiO3 lead to the induced magnetism, which is illustrated in terms of the exchange splitting between spin subbands through the crystal field theory and Jahn–Teller distortion effects. Our work proposes a simple method for fabricating lead-free ferroelectric materials with ferromagnetism property for multifunctional applications in smart electronic devices. [ABSTRACT FROM AUTHOR]

The new solid solution system of (1 − x)Bi1/2Na1/2TiO3 + xBi(Ti1/2Co1/2)O3 materials was fabricated using the sol–gel method. The structural studies via X-ray diffraction and Raman scattering indicated that Bi(Ti1/2Co1/2)O3 materials were well dissolved into host Bi1/2Na1/2TiO3 materials to follow the rhombohedral structure of host materials. The diffuse cations of Bi(Ti1/2Co1/2)O3 to random incorporation with host lattice to form as solid solution in host Bi1/2Na1/2TiO3 materials resulted in distortion lattice parameter and reduced the optical band-gap values from 3.06 to 2.32 eV for pure and 9 mol% Bi(Ti1/2Co1/2)O3 solute into host Bi1/2Na1/2TiO3 materials. The compensative diamagnetism and weak ferromagnetism of pure Bi1/2Na1/2TiO3 materials were tuned to ferromagnetism at room temperature as increasing the Bi(Ti1/2Co1/2)O3 amounts solute into host Bi1/2Na1/2TiO3 materials. The observation of the room-temperature ferromagnetism in Bi(Ti1/2Co1/2)O3-modified Bi1/2Na1/2TiO3 system was important to integrate the ferromagnetic properties in lead-free ferroelectric materials for further application in smart electronic devices which were required multifunctional materials. [ABSTRACT FROM AUTHOR]

A new (1-x)Bi0.5Na0.5TiO3 + xMgCoO3-δ solid solution system was synthesized using the simple sol–gel method. The structure that was investigated via X-ray diffraction and Raman scattering analysis indicated that the MgCoO3-δ materials were highly soluble into the host Bi0.5Na0.5TiO3 crystals. The random incorporation of Mg and Co cations into the host crystal of the Bi0.5Na0.5TiO3 materials reduced the optical band gap energy and induced a complex magnetic behavior as a function of MgCoO3−δ concentration solute in the host matrix. The optical band gap energy values decreased from 3.05 eV for pure Bi0.5Na0.5TiO3 materials to 2.22 eV with 9 mol% MgCoO3-δ solution for the Bi0.5Na0.5TiO3 compounds. A weak ferromagnetic property with strongly induced diamagnetism was obtained at room temperature for the pure Bi0.5Na0.5TiO3 materials, whereas ferromagnetic properties were observed for the MgCoO3-δ-modified Bi0.5Na0.5TiO3 compounds. The addition of paramagnetic and/or antiferromagnetic-like behavior was obtained for the MgCoO3-δ solid solution with over 5 mol% in the host Bi0.5Na0.5TiO3 materials. This work contributes to the current understanding of the interaction of transition metal cations in the host crystal ABO3 perovskite of lead-free ferroelectric materials due to the co-modification of A and B sites. [ABSTRACT FROM AUTHOR]

(1 − x)Bi0.5Na0.5TiO3 + xSrCoO3−δ solid-solution system was synthesised through the simple sol–gel technique. X-ray diffraction and Raman scattering analyses were used to study the structure of (1 − x)Bi0.5Na0.5TiO3 + xSrCoO3−δ system. Results showed that the SrCoO3−δ materials dissolved well into the host Bi0.5Na0.5TiO3 crystal. The random incorporation of Sr and Co cations into the host Bi0.5Na0.5TiO3 crystal to form a solid solution resulted in reduced optical band-gap energy and induced the complex magnetic properties of host Bi0.5Na0.5TiO3 materials. The optical band-gap energy of pure Bi0.5Na0.5TiO3 materials was estimated to be approximately 3.09 eV, which decreased to 2.18 eV for 9 mol% SrCoO3−δ solute incorporated into Bi0.5Na0.5TiO3 materials. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned as a function of SrCoO3−δ concentration added into the host Bi0.5Na0.5TiO3 materials. The enhanced magnetic performance in SrCoO3−δ-modified Bi0.5Na0.5TiO3 materials can be possibly applied in multifunction materials for electronic devices. [ABSTRACT FROM AUTHOR]

• New compound (1 − x)Bi 0.5 Na 0.5 TiO 3 + x MgMnO 3− δ solid solution was synthesized. • Magnetization of Bi 0.5 Na 0.5 TiO 3 samples was enhanced via MgMnO 3− δ as solid solution. • The E g values of Bi 0.5 Na 0.5 TiO 3 compounds decreased with increasing amount of MgMnO 3− δ. • A -site and B -site-co-modified Bi 0.5 Na 0.5 TiO 3 in the magnetic and optical properties were discussed. The phase structural, optical and magnetic properties of a new (1 − x)Bi 0.5 Na 0.5 TiO 3 + x MgMnO 3− δ compound were investigated. The MgMnO 3− δ -modified Bi 0.5 Na 0.5 TiO 3 materials were fabricated using sol–gel method. Results of X-ray diffraction and Raman scattering indicated that the MgMnO 3− δ materials were good solid solutions in the Bi 0.5 Na 0.5 TiO 3 compound. The random distribution of Mg and Mn cations in the host lattice of Bi 0.5 Na 0.5 TiO 3 materials reduced the optical band gap from 3.11 eV to 1.99 eV for 9 mol% MgMnO 3− δ -modified Bi 0.5 Na 0.5 TiO 3 materials. The complex magnetic behaviour in MgMnO 3− δ -modified Bi 0.5 Na 0.5 TiO 3 materials was obtained. The weak ferromagnetism vs. diamagnetism transformed to ferromagnetism vs. para/antiferromagnetic property depending on the concentration of MgMnO 3− δ solid solution in Bi 0.5 Na 0.5 TiO 3 samples. Our work can further contribute to the study of current injection ferromagnetic material in host lead-free ferroelectric materials for smart electronic device application. [ABSTRACT FROM AUTHOR]

Pb-free ferroelectric solid solution of Bi0.5K0.5TiO3 with BiCoO3 has been fabricated using a sol-gel technique, exhibiting room-temperature ferromagnetism. The optical bandgap of Bi0.5K0.5TiO3 reduced from 3.21 eV to 1.77 eV with increasing amount of BiCoO3 solid solution. The room-temperature ferromagnetism and bandgap reduction occurred due to BiCoO3 diffusion into Bi0.5K0.5TiO3, resulting in formation of solid solution. These results provide a simple approach to realize room-temperature ferromagnetism in Pb-free ferroelectric materials. [ABSTRACT FROM AUTHOR]

A new binary (1- x)Bi 1/2 Na 1/2 TiO 3 + x Ho 1/2 Na 1/2 TiO 3 solid solution system was synthesized by a simple chemical method. The crystal structure of (1- x)Bi 1/2 Na 1/2 TiO 3 + x Ho 1/2 Na 1/2 TiO 3 system was characterized by X-ray diffraction, showing that the crystal structure of the system followed the rhombohedral structure with symmetry of Bi 1/2 Na 1/2 TiO 3 materials. The distortion lattice parameters of Bi 1/2 Na 1/2 TiO 3 resulted from the random distribution of Ho impurity cations into the host lattice of Bi 1/2 Na 1/2 TiO 3 materials to form the solution. The direct optical bandgap energy of Bi 1/2 Na 1/2 TiO 3 materials was slightly changed in the range of 3.04–2.99 eV after the addition of Ho 1/2 Na 1/2 TiO 3. The strong enhancement in photoemission properties of Bi 1/2 Na 1/2 TiO 3 materials was related to electron transition from 5S 2 to 5I 8 level of Ho3+ cations randomly incorporated with the host Bi 1/2 Na 1/2 TiO 3 lattice. We expected our work to open a new simple way to integrate the photoluminescence properties in lead-free ferroelectric materials for further smart optoelectronic devices application. • New binary (1-x)Bi 1/2 Na 1/2 TiO 3 +xHo 1/2 Na 1/2 TiO 3 compounds was synthesized. • The optical band gap values of Bi 1/2 Na 1/2 TiO 3 materials were obtained as function of Ho 1/2 Na 1/2 TiO 3 addition. • The strong read emission were obtained in Ho 1/2 Na 1/2 TiO 3 -modified Bi 1/2 Na 1/2 TiO 3 system. • The simple method for integration photoluminescent were proposed. [ABSTRACT FROM AUTHOR]

• New (1 − x)Bi 0.5 Na 0.5 TiO 3 + x CaMnO 3- δ solid solution compounds was synthesized. • Ferromagnetism ordering at room temperature in Bi 0.5 Na 0.5 TiO 3 samples was enhanced via CaMnO 3- δ -modified. • The E g values of Bi 0.5 Na 0.5 TiO 3 compounds decreased with increasing amount of CaMnO 3- δ. • A -site and B -site-co-modified Bi 0.5 Na 0.5 TiO 3 in the magnetic and optical properties were discussed. CaMnO 3- δ -modified Bi 0.5 Na 0.5 TiO 3 was fabricated by using a sol–gel method. In the modified Bi 0.5 Na 0.5 TiO 3 , a single perovskite with distorted structure was obtained due to the random distribution of Ca and Mn cations in the host lattice. The co-modification in A - and B -sites of Bi 0.5 Na 0.5 TiO 3 via Ca and Mn resulted in the reduction of optical band gap and induction of room-temperature ferromagnetism. Co-modification of A - and B -sites in lead-free ferroelectric Bi 0.5 Na 0.5 TiO 3 is suitable for fabricating smart materials in electronic devices. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

A solid solution of NiTiO3 in Bi0.5Na0.5TiO3 materials was fabricated by sol-gel technique. According to the X-ray diffraction analysis, (1 − x)Bi0.5Na0.5TiO3 + xNiTiO3 materials exhibited a rhombohedral structure following the Bi0.5Na0.5TiO3 crystal symmetry. The random distribution of Ni cations into the host lattice of Bi0.5Na0.5TiO3 materials decreased the optical band gaps from 3.06 to 2.74 eV for 9 mol.% NiTiO3 solid solution. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned from weak ferromagnetism to ferromagnetism and of compensation of ferromagnetism with diamagnetic and/or antiferromagnetic property. This work provides understanding of the role of exchange interaction of cation transition metals to integrate magnetic properties in lead-free ferroelectric materials for smart multifunctional electronic devices. [ABSTRACT FROM AUTHOR]

The integration of ferromagnetism in lead-free ferroelectric materials is important to fabricate smart materials for electronic devices. In this work, (1 −  x )Bi 0.5 Na 0.5 TiO 3  +  x MgFeO 3- δ materials ( x  = 0–9 mol%) were prepared through sol–gel method. X-ray diffraction characterization indicated that MgFeO 3- δ materials existed as a well solid solution in lead-free ferroelectric Bi 0.5 Na 0.5 TiO 3 materials. The rhombohedral structure of Bi 0.5 Na 0.5 TiO 3 materials was distorted due to the random distribution of Mg and Fe cations into the host lattice. The reduced optical band gap and the induced room-temperature ferromagnetism were due to the spin splitting of transition metal substitution at the B -site of perovskite Bi 0.5 Na 0.5 TiO 3 and the modification by A -site co-substitution. This work elucidates the role of secondary phase as solid solution in Bi 0.5 Na 0.5 TiO 3 material for development of lead-free multiferroelectric materials. [ABSTRACT FROM AUTHOR]

A new binary (1- x)Bi 1/2 Na 1/2 TiO 3 + x Eu 1/2 Na 1/2 TiO 3 system was synthesized by a simple chemical method. X-ray diffraction and Raman scattering studies on the crystal structure of Eu 1/2 Na 1/2 TiO 3 -modified Bi 1/2 Na 1/2 TiO 3 materials proved that Eu 1/2 Na 1/2 TiO 3 was well dissolved into the host Bi 1/2 Na 1/2 TiO 3 materials. The random incorporation of impurity cations of Eu 1/2 Na 1/2 TiO 3 materials during solute into host Bi 1/2 Na 1/2 TiO 3 crystal resulted in compressing the rhombohedral structure of the host material. The random distribution of impurity cations of Eu 1/2 Na 1/2 TiO 3 into the host Bi 1/2 Na 1/2 TiO 3 lattices exhibited a complex change in the optical bandgap of pure Bi 1/2 Na 1/2 TiO 3 materials with the value ranging from 3.04 eV to 2.89 eV. Strong photoemission of Eu 1/2 Na 1/2 TiO 3 -modified Bi 1/2 Na 1/2 TiO 3 materials obtained at room temperature was related to electron transition from 4 f -4 f levels of Eu3+ cations incorporated with the host lattice. We expected our work to provide a simple method to integrate the photoluminescence properties in lead-free ferroelectric materials for innovative electronic applications. • New binary (1-x)Bi 1/2 Na 1/2 TiO 3 +xEu 1/2 Na 1/2 TiO 3 compounds was synthesized. • The optical band gap values of Bi 1/2 Na 1/2 TiO 3 materials were obtained as function of Eu 1/2 Na 1/2 TiO 3 addition. • The strong red emission was obtained in Eu 1/2 Na 1/2 TiO 3 -modified Bi 1/2 Na 1/2 TiO 3 system. • The simple method for integration photoluminescent in lead-free ferroelectric materials were proposed. [ABSTRACT FROM AUTHOR]

In this work, the Sm 1/2 Na 1/2 TiO 3 -addition Bi 1/2 Na 1/2 TiO 3 materials as solid solutions were synthesized via a chemical route method. The X-ray diffraction and Raman scattering results indicated that Sm 1/2 Na 1/2 TiO 3 materials were well solute into the host Bi 1/2 Na 1/2 TiO 3 materials to form solid solutions. The optical bandgap of the pure Bi 1/2 Na 1/2 TiO 3 materials was estimated from ultraviolet–visible spectroscopy of 3.07 eV. The bandgap slightly reduced to 2.94 eV as increasing the Sm 1/2 Na 1/2 TiO 3 amounts up to 9 mol.%. Strong photoluminescence (PL) of Sm 1/2 Na 1/2 TiO 3 -addition Bi 1/2 Na 1/2 TiO 3 materials was obtained in the visible wavelength range of 550–750 nm which related to photoluminescence of Sm cations randomly incorporated into the host lattice of Bi 1/2 Na 1/2 TiO 3 materials. Our work was promised to show a new method to integrate the PL properties in lead-free ferroelectric materials. • New solid solution (1− x)Bi 1/2 Na 1/2 TiO 3 + x Sm 1/2 Na 1/2 TiO 3 materials was synthesized. • The optical band gap energy of Bi 1/2 Na 1/2 TiO 3 materials were complex changed. • The strong photoemission properties were obtained for 5 mol.% Sm 1/2 Na 1/2 TiO 3 -modification Bi 1/2 Na 1/2 TiO 3 compounds. • This work demonstrated a new method to integrate photoemission in lead-free ferroelectric materials. [ABSTRACT FROM AUTHOR]

A solid solution of NiTiO3 in Bi0.5Na0.5TiO3 materials was fabricated by sol-gel technique. According to the X-ray diffraction analysis, (1 − x)Bi0.5Na0.5TiO3 + xNiTiO3 materials exhibited a rhombohedral structure following the Bi0.5Na0.5TiO3 crystal symmetry. The random distribution of Ni cations into the host lattice of Bi0.5Na0.5TiO3 materials decreased the optical band gaps from 3.06 to 2.74 eV for 9 mol.% NiTiO3 solid solution. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned from weak ferromagnetism to ferromagnetism and of compensation of ferromagnetism with diamagnetic and/or antiferromagnetic property. This work provides understanding of the role of exchange interaction of cation transition metals to integrate magnetic properties in lead-free ferroelectric materials for smart multifunctional electronic devices. [ABSTRACT FROM AUTHOR]