Figure 1

Measured tunnel conductances (dotted lines) for CE-I-N-S junctions at 300 mK. A finite perpendicular magnetic field of 100 G is used to drive the Al slab into the normal state. The fit (solid lines) with theory is in quantitative agreement with experiment and provides a measure of the electron-spin fluctuation renormalization factor (see Table ). Inset: Junction geometry.Reuse & Permissions

Figure 2

DOS for Ni concentration for 2.4%, 5.5%, and 7% measured at 300 mK (dotted lines). The thickness of the ${\mathrm{P}\mathrm{d}}_{1-x}{\mathrm{N}\mathrm{i}}_x$ was kept constant, equal to 50 Å. The minigap disappears at the transition between the paramagnetic state and the ferromagnetic state. For concentrations higher than 4.0% the only energy scale is the Nb energy gap. Quantitative fits (solid lines) provide a measurement of the depairing energy at Ni concentrations above 2.4% (see Table ). Inset: Onset of ferromagnetic order probed at $T=1.5\mathrm{K}$ by AHE in 50 Å-thick ${\mathrm{P}\mathrm{d}}_{1-x}{\mathrm{N}\mathrm{i}}_x$. An anomalous component appears above $x\sim 2.5\%$ and a hysteresis loop for $x\sim 7.0\%$.Reuse & Permissions

Figure 3

Densities of states measured in the ferromagnetic state for Ni concentrations above 5.5% at 300 mK (dashed lines). For clarity, the spectra are scaled to that corresponding to 5.5% Ni. Only one characteristic energy scale, the energy gap of Nb $\Delta$ (about 1.35 meV), is observed, suggesting that finite size effects are irrelevant. The semi-infinite limit for the ferromagnetic layer is recovered. The fit (thick solid line), using the Eq. (5), allows us to deduce the exchange field.Reuse & Permissions

Figure 4

Measured depairing energy (squares, left axis) as a function of Ni concentration. Three regimes occur. In the spin fluctuation regime, the depairing $\Gamma$ displays no variation with Ni concentration as long as the latter remains below 2.5%. Ferromagnetism sets in for Ni concentrations above 2.5%, the dominant depairing mechanism then being AG-like. Long-range ferromagnetic order occurs at Ni concentrations above 7%, and hysteresis appears in the Hall signal. The Hall signal increase roughly linearly below 7% (open circles, right axis) and displays an up turn above 7% (solid circles, right axis).Reuse & Permissions