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A core challenge in understanding high entropy oxides (HEOs) is how these systems, with five or more cations at a crystallographic site, can withstand local distortions while preserving a uniform structure on a larger scale. We address this for spinel HEO by comparatively examining extended X-ray absorption fine structure (EXAFS) on (Mn$_{0.2}$Co$_{0.2}$Ni$_{0.2}$Cu$_{0.2}$Zn$_{0.2}$)Cr$_2$O$_4$ ($A^5$Cr$_2$O$_4$) and its parent counterparts $A$Cr$_2$O$_4$ ($A$= Mn, Co, Ni, Cu, Zn). Unlike the HEO with rock-salt structure, the element-specific distortions in disordered sublattice go beyond the first neighbor here. Moreover, the tetragonal distortion around the Cu$^{2+}$ ion, known as a textbook example of the Jahn-Teller effect, is highly reduced in $A^5$Cr$_2$O$_4$ compared to CuCr$_2$O$_4$. Despite variations in the A-O bond lengths, the inter-cationic distances remained remarkably similar. This affirms a high level of flexibility in the positioning of oxygen, enabling them to adapt to the overall cubic symmetry. Despite containing multiple magnetic ions, the Curie-Weiss temperature and effective magnetic moments of $A^5$Cr$_2$O$_4$ are similar to those of NiCr$_2$O$_4$. This can be attributed to both materials' comparable local bond lengths around Cr, as evidenced by EXAFS analysis. This study conclusively presents a method for elucidating how local structural distortions influence the macroscopic properties of compositionally complex quantum materials.

In the present study, we have discussed the up-turn behavior in the resistivity pattern of the topological nodal line semimetal InBi. We argued that such nature could be generalized with a mathematical model, that can be applied to any compounds exhibiting similar behavior. The extremely high magnetoresistance (XMR) has also been explained by the carrier compensation in the compound, estimated from the Hall conductivity. Moreover, from the study of Subhnikov-de Haas (SdH) oscillation and density functional theory (DFT), we obtained the complete three-dimensional (3D) Fermi surface topology of the compound InBi. A detailed understanding of carriers' behavior has been discussed using those studies. We have also unfurled the topology of each electron and hole pocket and its possible modulation with electron and hole doping.

In the present work, a thin film was deposited on quartz substrate by reactive RF magnetron sputtering of high purity (99.999%) aluminium target using ultra-high pure (Ar + N2) gas mixture. The percentage ratio of Ar and N2 in the gas mixture was 95% and 5%, respectively. Chemical characterization using x-ray photoelectron spectroscopy (XPS) and energy-dispersive xray (EDX) spectroscopy reveals that in the presence of dilute nitrogen, Al prefers to react with residual oxygen to form Al2O3 while the nitrogen is incorporated in it. The stoichiometry of bulk film is Al2N0.38O3.1. Magnetic and electrical properties measurement shows that the film exhibits ntype dilute magnetic semiconductor (DMS) property at 300K. The film has low electrical resistivity of 6.3 {\Omega}-cm and high carrier mobility of 5.7*106 cm2V-1s-1 at 300K. A density functional theory (DFT) calculation was performed to investigate the origin of observed magnetism in the film. From first-principles calculation based on DFT, it is found that for thermodynamic stability dilute nitrogen incorporated in Al2O3 preferred to sit at the interstitial site, which is responsible for observed magnetic property. Present study reported here provides a new insight to prepare rarely observed n-type DMS at room temperature by incorporating nitrogen interstitials in Al2O3, which is desirable for potential application in the field of spintronics.

In this work, we studied cobalt nitride (Co-N) thin films deposited using a dc magnetron sputtering method at a substrate temperature (\Ts) of 523\,K. We find that independent of the reactive gas flow (\pn) used during sputtering, the phases of Co-N formed at this temperature seems to be identical having N \pat~$\sim$5. This is contrary to Co-N phases formed at lower \Ts. For \Ts$\sim$300\,K, an evolution of Co-N phases starting from Co(N)$\rightarrow$\tcn$\rightarrow$Co$_3$N$\rightarrow$CoN can be seen as \pn increases to 100\p, whereas when the substrate temperature increases to 523\,K, the phase formed is a mixture of Co and \tcn, independent of the {\pn} used during sputtering. We used x-ray diffraction (XRD) to probe long range ordering, x-ray absorption spectroscopy (XAS) at Co absorption edge for the local structure, Magneto-optical Kerr e ffect (MOKE) and polarized neutron reflectivity (PNR) to measure the magnetization of samples. Quantification of N \pat~was done using secondary ion mass spectroscopy (SIMS). Measurements suggest that the magnetic moment of Co-N samples deposited at 523\,K is slightly higher than the bulk Co moment and does not get affected with the \pn~used for reactive sputtering. Our results provide an important insight about the phase formation of Co-N thin films which is discussed in this work., Comment: 6 pages, 5 figures