New (1-x)Bi 0.5 na 0.5 tio 3 + xcafeo 3-δ solid solution compounds were fabricated using a sol-gel method. the cafeo 3-δ materials were mixed into host Bi 0.5 na 0.5 tio 3 materials to form a solid solution that exhibited similar crystal symmetry to those of Bi 0.5 na 0.5 tio 3 phases. The random distribution of Ca and fe cations in the Bi 0.5 na 0.5 tio 3 crystals resulted in a distorted structure. The optical band gaps decreased from 3.11 eV for the pure Bi 0.5 na 0.5 tio 3 samples to 2.34 eV for the 9 mol% CaFeO 3-δ -modified Bi 0.5 na 0.5 tio 3 samples. Moreover, the Bi 0.5 na 0.5 tio 3 samples exhibited weak photoluminescence because of the intrinsic defects and suppressed photoluminescence with increasing cafeo 3-δ concentration. Experimental and theoretical studies via density functional theory calculations showed that pure Bi 0.5 na 0.5 tio 3 exhibited intrinsic ferromagnetism, which is associated with the possible presence of Bi, Na, and Ti vacancies and Ti 3+ -defect states. Further studies showed that such an induced magnetism by intrinsic defects can also be enhanced effectively with CaFeO 3-δ addition. This study provides a basis for understanding the role of secondary phase as a solid solution in Bi 0.5 na 0.5 tio 3 to facilitate the development of lead-free ferroelectric materials.The integration of room-temperature ferromagnetic behavior in lead-free ferroelectric materials is a new research trend for the development of green functional materials in smart electronic devices 1,2 . PbTiO 3 -based compounds are one of the most commonly used ferroelectric materials in electronic devices 3 . Therefore, ferroelectric PbTiO 3 -based materials with improved magnetic properties have the potential for the fabrication of next-generation electronic devices.First, the self-organized ferromagnetism of pure ferroelectric PbTiO 3 materials was investigated. The experimental results showed that the weak ferromagnetism in undoped PbTiO 3 nanocrystalline at room temperature resulted from intrinsic defects in events such as O and Ti vacancies 4 . PbTiO 3 thin films also exhibited room-temperature ferromagnetism because of defects in the crystal quality of the film during growth 5 . Shimada et al. predicted that both O and Ti vacancies induce ferromagnetism but through different mechanisms. The ferromagnetism driven by O vacancies originated from the spin-polarized e g state of the nearest Ti atom, whereas that directed by Ti vacancies was attributed to the half-metallic p x state of the nearest O atom 6 . In addition, the ferroelectric property of PbTiO 3 materials at room temperature could be attributed to O vacancies formed on the surfaces, such as vacancies induced ferromagnetism due to local non-stoichiometry and orbital symmetry breaking 7 . Xu et al. conducted first-principle calculations and reported that the O vacancies that formed at the domain wall led to magnetism with a localized spin moment around the vacancies 8 . Second, the conversion of transition metals to ferroelectric PbTiO 3 materials was studied...

MXene V2C structure provides a specific theoretical capacity as high as 472 mA h g−1 at the Li2V2C stoichiometry and extremely fast diffusion with an energy barrier less than 0.1 eV. These intriguing findings are robust against intrinsic structural defects.

An ultrahigh energy storage performance is achieved in the BNST-20% (Sc0.5Ta0.5)4+ ceramic via chemical modification, which could induce the evolution of oxygen vacancies and local polar phases to achieve a high saturation polarization.

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Ab initio electronic structure calculations reveal that interstitial 2p elements (B, C, and N) have dramatic effects on the structural stability and intrinsic magnetic properties of L10-phase FeNi. Among the 3 possible interstitial impurities, only the B improves the L10-phase stability of FeNi and enhances its uniaxial magnetic anisotropy (0.7 MJ m−3) up to 2.6 MJ m−3. The underlying mechanism is elucidated in terms of single-particle energy spectra analyses along with atom- and orbital-resolved magnetocrystalline anisotropy energy, where both the Fe and Ni 3d level changes induced by charge rearrangement and 2p-3d hybridization are responsible. These findings point toward feasibility of enhancing the structural stability and energy product of 3d-only magnetic metals through the interstitial doping with 2p nonmetal elements.