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Highly transparent lead‐free (1‐x)K0.5Na0.5NbO3–xSr(Zn1/3Nb2/3)O3 (KNN–xSZN) ferroelectric ceramics have been synthesized via a conventional pressureless sintering method. All samples are optically clear, showing high transmittance in the visible and near‐infrared regions (~70% and ~80% at 0.5 mm of thickness, respectively). This exceptionally good transmittance is due to the pseudo‐cubic phase structure as well as the dense and fine‐grained microstructure. In addition, a high energy storage density of 3.0 J/cm3 has been achieved for the 0.94K0.5Na0.5NbO3–0.06Sr(Zn1/3Nb2/3)O3 ceramics with submicron‐sized grains (~136 nm). The main reason is likely to be the typical relaxor‐like behavior characterized by diffuse phase transition, in addition to the dense and fine‐grained microstructure. This study demonstrates that the 0.94K0.5Na0.5NbO3–0.06Sr(Zn1/3Nb2/3)O3 ceramic is a promising candidate of lead‐free transparent ferroelectric ceramics for new areas beyond transparent electronic device applications.

Ferromagnetic (FM) two-dimensional (2D) transition metal dichalcogenides (TMDs) have potential applications in modern electronics and spintronics and doping of TMDs with transition metals can enhance the magnetic characteristics. In this work, the structural stability, electronic states, and magnetic properties of Mn-doped monolayer/bilayer MoS are studied systematically by first-principles calculations. Substitutional Mn dopants at the Mo sites are energetically favorable in both monolayer and bilayer MoS under the S-rich condition which is common in the synthesis of MoS nanosheets. Two Mn dopants participate in the FM interaction in monolayer MoS and magnetic coupling of two Mn dopants via the double-exchange mechanism can be mediated by the nearest neighboring S. Magnetic coupling can be ascribed to the competition between the double-exchange, direct-exchange, and super-exchange interactions, which take place between two Mn dopants in bilayer MoS with the MnMn, MnMn and Mn-Mn configurations. Our results reveal the geometrical dependence of magnetic-exchange coupling suggesting that Mn-doped monolayer/bilayer MoS has large potential in spintronic devices.

High transparency was obtained in (1-x)(K 0.5 Na 0.5)NbO 3-xSr(Mg 1/3 Nb 2/3)O 3 (x = 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08) lead-free ceramics by pressure-less sintering procedure. The effects of Sr(Mg 1/3 Nb 2/3)O 3 content on the microstructure, phase transition, optical properties and electrical properties were studied in detail. The X-ray diffraction results showed that the crystal structure of ceramics gradually transformed from orthorhombic phase into pseudo-cubic phase with doping of Sr(Mg 1/3 Nb 2/3)O 3 ,. The fine grain microstructure with clear grain boundary was observed in all compositions, while the grain size exhibited significant composition dependence. It was found that a more uniform distribution with smaller grain size was favorable to high optical transmittance, owing to the decreased scattering by grains and grain boundaries. In addition, a strong diffuse phase transformation in KNN-based ceramics induced by Sr(Mg 1/3 Nb 2/3)O 3 doping, causing the ceramics become more relaxor-like and transparent. The transmittance and electric properties results indicated that the 0.95(K 0.5 Na 0.5)NbO 3-0.05Sr(Mg 1/3 Nb 2/3)O 3 ceramics exhibited higher transmittance (60% in the near-IR region) accompanied with better electrical properties ( m = 2104, P r = 5.0 μC/cm 2 , d 33 = 92 pC/N).