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While hydrogen-rich materials have been demonstrated to exhibit high T_csuperconductivity at high pressures, there is an ongoing search for ternary, quaternary, and more chemically complex hydrides that achieve such high critical temperatures at much lower pressures. First-principles searches are impeded by the computational complexity of solving the Eliashberg equations for large, complex crystal structures. Here, we adopt a simplified approach using electronic indicators previously established to be correlated with superconductivity in hydrides. This is used to study complex hydride structures, which are predicted to exhibit promisingly high critical temperatures for superconductivity. In particular, we propose three classes of hydrides inspired by the Fm $\overline{3}$ m RH ${}_3$ structures that exhibit strong hydrogen network connectivity, as defined through the electron localization function. The first class [RH ${}_{11}$ X ${}_3$ Y] is based on a Pm $\overline{3}$ m structure showing moderately high T_c, where the T_cestimate from electronic properties is compared with direct Eliashberg calculations and found to be surprisingly accurate. The second class of structures [(RH ${}_{11}$ ) ${}_2$ X ${}_6$ YZ] improves on this with promisingly high density of states with dominant hydrogen character at the Fermi energy, typically enhancing T_c. The third class [(R ${}^1$ H ${}_{11}$ )(R ${}^2$ H ${}_{11}$ )X ${}_6$ YZ] improves the strong hydrogen network connectivity by introducing anisotropy in the hydrogen network through a specific doping pattern. These design principles and associated model structures provide flexibility to optimize both T_cand the structural stability of complex hydrides. 

Heavy fermion characteristics and potential superconductivity are observed in the partially vacancy-ordered Y₄Fe_xGe₈. 

Abstract Ferrimagnets, which have both ferromagnetic and antiferromagnetic coupling, are attracting increased attention in the realm of spintronic devices due to advantages such as ultrafast dynamics and a suppressed skyrmion Hall effect. Thus, understanding the behavior of nontrivial spin textures in ferrimagnets is crucial; however, comprehensive reports on this topic remain limited. Here, the magnetic spin textures of ferrimagnetic Mn_{2 −x}Zn_xSb (x = 0.85) is explored as a function of temperature and applied magnetic field. The spin textures can be tuned to a variety of states, including stripes, skyrmion bags, and a skyrmion lattice. Chiral Néel‐type magnetic structures are visualized using Lorentz transmission electron microscopy. Mn(I) ions are slightly shifted toward the Sb sites, which may be due to a strong electrostatic interaction between Mn and Sb ions. This local structural distortion breaks the inversion symmetry and introduces an effective Dzyaloshinkii–Moriya interaction. This work thus provides a pathway to use doping and heterogeneity in a ferrimagnet to control and generate chiral nontrivial spin textures.