An enhancement of the superconducting transition temperature and development of an additional magnetic component in the superconducting state, initiated by inhomogeneous spin anti-screening are demonstrated in In/Ni nanoparticle composites. A significant 9% increase of the superconducting transition temperature as a consequence of the magnetic proximities is detected. Unconventional cross-shaped magnetization hysteresis loops appear in densely packed assemblies, where magnetization increases, rather than decreases, upon entering the superconducting state in field-decreasing loops. Surprisingly, magnetization in the superconducting state can reach values as large as 3.5 times the saturation magnetization revealed in the normal state.
- In nanoparticle