Superconducting Properties and Enhanced Upper Critical Field in η-Carbide-Type Oxide Zr₄Rh₂O: A Theoretical and Experimental Analysis

Abstract

The η-carbide-type oxides have emerged as a promising class of superconductors due to their unique structural and electronic properties. In this study, we investigate the superconducting behavior of Zr₄Rh₂O through theoretical modeling and experimental data analysis. We introduce a novel parameter E defined as:

E = 0.355A + (0.163 - 0.031A)·wt% - 1.898

where A is the weighted average of elemental contributions to superconductivity. Our calculations reveal that Zr₄Rh₂O exhibits:

- Superconducting transition temperature T_c = 3.73 K

- Upper critical field μ₀H_c2(0) = 6.16 T

- Pauli limit μ₀H_p = 7.59 T

2

The parameter E ≈ 9.41 correlates well with observed properties, demonstrating weaker spin-orbit coupling effects compared to Pd-analogues.