MgB2 — Conventional Superconductor
Data: Nagamatsu et al., Nature 410, 63 (2001). R(T) from their Figure 2. Known Tc = 39K.
Results
| Feature | Known | DSF-AI |
|---|
| Transition temperature | 39K | 38–39K (transitions detected) |
| Precursor onset | Not reported | VOLATILE region extends to 56K — 17K above Tc |
| Zero-resistance state | Below 36K | STABLE from 2K to 36K |
Stability Map
| Region | Range | Interpretation |
|---|
| STABLE | 2 — 36K | Superconducting state — zero resistance |
| VOLATILE | 36 — 56K | Transition region with precursors above Tc |
| DEGENERATE | 56 — 300K | Normal metallic state |
Notable finding: MgB2 is a conventional BCS superconductor. Precursors above Tc in a BCS system are unexpected and may indicate superconducting fluctuation effects not previously characterized in this material. DSF-AI detected these from the R(T) curve alone.