High entropy oxides (HEOs) are a class of materials, containing equimolar portions of five or more transition metal and/or rare-earth elements. We report here about the layer-by-layer growth of HEO [(La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 )NiO 3 ] thin films on NdGaO 3 substrates by pulsed laser deposition. The combined characterizations with in-situ reflection high energy electron diffraction, atomic force microscopy, and X-ray diffraction affirm the single crystalline nature of the film with smooth surface morphology. The desired +3 oxidation of Ni has been confirmed by an element sensitive X-ray absorption spectroscopy measurement. Temperature dependent electrical transport measurements revealed a first order metal-insulator transition with the transition temperature very similar to the undoped NdNiO 3 . Since both of these systems have a comparable tolerance factor, this work demonstrates that the electronic behaviors of A-site disordered perovskite-HEOs are primarily controlled by the average tolerance factor.Finding new materials and new ways to tune material's properties are essential to fulfill the demand of the constantly evolving modern technology. Transition metal oxides show various fascinating electronic and magnetic phenomena such as metal-insulator transition, superconductivity, colossal magnetoresistance, multiferroicity, skyrmions, etc., which have lots of prospect for technological applications 1-6 . Furthermore, transition metal (TM) based high entropy oxides (HEOs) are being explored in recent years to achieve tunable properties in unexplored parts of complex phase diagram 7-21 . In general, the configurational entropy of a multi-component solid solution can be enhanced by mixing a large number of cations in equiatomic proportions and a single structural phase is formed if the entropy contribution overcomes enthalpy driven phase separation (∆G mix =∆H mix -T ∆S mix ; ∆G mix , ∆H mix , ∆S mix are Gibbs free energy, enthalpy and entropy of mixing, respectively) 7,18 . After the report of the first HEO [Mg 0.2 Ni 0.2 Co 0.2 Cu 0.2 Zn 0.2 O with rocksalt structure] by Rost et al. 7 , HEOs with other structural symmetry such as perovskite 15,17 , spinel 16 have been also synthesized. However, this promising field of HEO is at a very early stage and most of the aspects of HEOs are yet to be explored experimentally. For example, it is still unknown whether the strong disorder or the average tolerance factor (t avg ) determines the electronic and magnetic behaviors of perovskite-HEOs.As a prototypical example of perovskite (ABO 3 ) series, RENiO 3 (RE= La, Pr, Nd, Sm, Eu...Lu) exhibits an interesting phase diagram as a function of tolerance factor (t= R RE +RO √ 2(RNi+RO) , where R RE , R Ni , R O are radii of RE, Ni and O, respectively) 22,23 . LaNiO 3 , the least distorted member of this series remains metallic and paramagnetic down to the lowest temperature. Bulk PrNiO 3 and NdNiO 3 (NNO) show temperature driven simultaneous transitions from an orthorhombic, paramagnetic, metallic phase to a monoclini...

PURPOSE:The purpose of this study is to determine if phacoemulsification with posterior chamber foldable intraocular lens implantation has a greater impact on the corneal endothelium of type 2 diabetic patients as compared to nondiabetic controls.MATERIALS AND METHODS:This study compared the corneal endothelial status in sixty patients with diabetes with good glycemic control and sixty nondiabetic controls before and after (1 week, 1 month, 2 month, and 3 month) uneventful phacoemulsification. Central corneal endothelial cell density, percentage hexagonality, and coefficient of variation were measured using a noncontact specular microscope. Central corneal thickness was taken as a surrogate marker for endothelium functional status.RESULTS:Data were age and sex matched. Patients with diabetes showed significantly higher loss in endothelial cell count as compared to nondiabetic controls. Furthermore, the patients with diabetes showed a slower recovery trend in the endothelial healing response as evidenced by lower change in the coefficient of variation. Significant correlation was found between energy used and change in endothelial count as well as coefficient of variation in nondiabetics only.CONCLUSION:In spite of good glycemic control, patients with diabetes have significantly more endothelial damage in comparison to nondiabetic controls with similar nuclear grading and phaco energy used. This warrants a more careful use of phaco energy in patient with diabetes.

No abstract

The discovery of skyrmions has recently sparked tremendous interest in topologically nontrivial spin textures. The signature of the noncoplanar nature of magnetic moments can be observed as topological Hall effect (THE) in electrical measurement. Realization of such nontrivial spin textures in new materials and through new routes is an ongoing endeavor due to their huge potential for future ultra‐dense, low‐power memory applications. In this work, oxygen vacancy (OV)‐induced THE and anomalous Hall effect (AHE) in a 5d0 system KTaO3 are reported. The observation of weak antilocalization behavior and THE in the same temperature range strongly implies the crucial role of spin–orbit coupling (SOC) behind the origin of THE. Ab initio calculations reveal the formation of the magnetic moment on Ta atoms around the OV and Rashba‐type spin texturing of conduction electrons. In the presence of Rashba SOC, the local moments around vacancy can form bound magnetic polarons (BMPs) with noncollinear spin texture, resulting in THE. Scaling analysis between transverse and longitudinal resistance establishes skew scattering‐driven AHE in the present case. This study opens a route to realize topological phenomena through defect engineering.

No abstract