OpenSmFe: An Open, Processing-Aware and Comparability-Graded Database of Samarium–Iron(–Nitrogen) Permanent-Magnet Properties

Abstract

Samarium–iron–nitride (Sm₂Fe₁₇N₃) is a leading rare-earth-lean candidate for high-performance permanent magnets, but its published properties are difficult to compare. The nitride decomposes below conventional sintering temperatures, so reported values come from loose powders, aligned powders, bonded magnets and low-temperature consolidated compacts, measured under conditions that papers often leave unstated. Text-mined materials databases now reach tens of thousands of entries, but they record a value without the processing route, sample form and measurement conditions that determine what the value means. We describe OpenSmFe, an open database in which every value is stored as published, converted to SI units, linked to a verbatim evidence sentence, and assigned an explicit A/B/C comparability grade with machine-readable reasons. The schema separates samples (composition, alloy route, milling, melt spinning, annealing, nitriding, consolidation, phase outcome and sample form) from measurements. We apply it to a seed release of 21 author-verified values from 14 samples in 6 open-access papers. No value attains the highest grade. The measurement temperature is unstated for 16 of the 19 values other than Curie temperatures, and the coercivity definition is unstated for 8 of 11 coercivities. The workflow also exposed an internal inconsistency in one source. It caught 1 misattributed and 3 paraphrased evidence statements in the AI-assisted first-draft extraction, all corrected before release. We propose a minimum reporting set for Sm–Fe–N magnet studies and release the data and code under open licenses.