In the present study, the structural and hitherto uninvestigated mechanical (elastic stiffness constants, machinability index, Cauchy pressure, anisotropy indices, brittleness/ductility, Poisson's ratio), electronic, optical, and thermodynamic properties of novel boron-rich compounds B₆X (X = S, Se) have been explored using density functional theory. The estimated structural lattice parameters were consistent with the prior report. The mechanical and dynamical stability of these compounds have been established theoretically. The materials are brittle in nature and elastically anisotropic. The value of fracture toughness, K_IC for the B₆S and B₆Se, are ∼ 2.07 MPam^0.5, evaluating the resistance to limit the crack propagation inside the materials. Both B₆S and B₆Se compounds possess high hardness values in the range of 31–35 GPa and have the potential to be prominent members of the class of hard compounds. Strong covalent bonding and sharp peak at low energy below the Fermi level confirmed by partial density of states (PDOS) resulted in the high hardness. The profile of band structure as well as density of states assesses the indirect semiconducting nature of the titled compounds. The comparatively high value of Debye temperature (Θ_D), minimum thermal conductivity (K_min), lattice thermal conductivity (k_ph), low thermal expansion coefficient, and low density suggest that both boron-rich chalcogenides might be used as thermal management materials. Large absorption capacities in the mid-ultraviolet region (3.2–15 eV) of the studied materials and low reflectivity (∼16%) are significantly noted. Such favorable features give promise to the compounds under investigation to be used in UV surface-disinfection devices as well as medical sterilizer equipment applications. Excellent correlations are found among all the studied physical properties of these compounds.

Structural properties, impedance, dielectric and electric modulus spectra have been used to investigate the sintering temperature (Ts) effect on the single phase cubic spinel Ni0.6Zn0.4Fe2O4 (NZFO) ceramics synthesized by standard ceramic technique. Enhancement of dielectric constants is observed with increasing Ts. The collective contribution of n-type and p-type carriers yields a clear peak in notable unusual dielectric behavior is successfully explained by the Rezlescu model. The non-Debye type long range dielectric relaxation phenomena is explained by electric modulus formalism. Fast response of the grain boundaries of the sample sintered at lower Ts sample leading to small dielectric spin relaxation time, t (several nanoseconds) have been determined using electric modulus spectra for the samples sintered at different Ts. Two clear semicircles in impedance Cole-Cole plot have also been successfully explained by employing two parallel RC equivalent circuits in series configuration taking into account no electrode contribution. Such a long relaxation time in NZFO ceramics could suitably be used in nanoscale spintronic devices.