In the last two decades, structure and properties of Ruddlesden-Popper phase (RP) A 2 BO 4 oxides with K 2 NiF 4 structure, have been widely investigated. But to the best of our knowledge, no review article is available in the literature on recent studies on these oxides. Therefore, in this article, recent studies on structure, electrical, dielectric, and optical properties of these oxides have been reviewed. Special attention is put on to highlight the effect of doping and oxygen stoichiometry on the structure and properties of these oxides. Further, important applications of these oxides have also been mentioned in this article.

We report on growth optimization and magnetodynamic properties of [Formula: see text]-W/Co[Formula: see text]Fe[Formula: see text]B[Formula: see text] system. We show that a relatively low growth rate of [Formula: see text][Formula: see text]Å/s is essential for the stabilization of the [Formula: see text] phase of tungsten. The low growth rate allows for the residual oxygen present in the chamber to get incorporated into the growing film, which helps in the stabilization of [Formula: see text]-phase tungsten as evidenced by X-ray diffraction and X-ray photoelectron spectroscopy. Using these optimized growth conditions, we achieved the [Formula: see text] phase in tungsten thin films up to a thickness of 60[Formula: see text]nm. The ferromagnetic resonance measurements of [Formula: see text]-W/Co[Formula: see text]Fe[Formula: see text]B[Formula: see text] show a linear behavior of the Gilbert damping constant with the inverse of the thickness of the CoFeB layer, from which, we calculated spin mixing conductance to be [Formula: see text][Formula: see text]m[Formula: see text]. Using the inverse spin Hall effect measurements, we obtained a large spin Hall angle of [Formula: see text] in [Formula: see text]-W, which is achieved without using oxygen plasma during growth of tungsten.

Summary Nanocrystalline powders of co‐doped ceria oxides Ce0.85La0.10Sr0.05O2‐δ (CLSO) and Ce0.85Gda0.10Sr0.05O2‐δ (CGSO) have been synthesized by auto combustion method at 100°C using sucrose as fuel. Thermal analysis (TGA/DSC) of as‐prepared powders indicated calcination above 400°C to remove organic residue. The average grain size of the pellets sintered at 1200°C for 4 hours is 436 and 683 nm for CLSO and CGSO, respectively. The electrical conductivity of the sintered samples was determined by impedance measurements in the temperature range 300°C to 600°C and the frequency range 20 Hz to 2 MHz. At 600°C, the total electrical conductivity (σt) of CGSO is 6.78 × 10−3 S cm−1, 2.5 times higher than 2.72 × 10−3 S cm−1 of CLSO. Further, it is found that the value of grain boundaries blocking factor (αgb) of CGSO is 0.47 which is 30% lesser than 0.68 of CLSO at 600°C. The higher value of electrical conductivity of CGSO as compared to CLSO is attributed to the lesser blocking effect of grain boundaries, smaller lattice distortion and denser microstructure of CGSO as compared to CLSO. The electrical conductivity of synthesized samples has been compared with the electrical conductivity of similar compositions of co‐doped CeO2 oxides. Our study indicated that the sintering temperature, and hence, the morphology of sintered samples has a significant role in determining the electrical conductivity. The presence of oxygen vacancies in the synthesized samples is experimentally supported by using UV‐visible spectroscopy, Raman spectroscopy, and thermal analysis techniques.

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