A research team led by Prof. Zhang Jinglei from Hefei Institutes of Physical Science, Chinese Academy of Sciences, found that the trilayer nickelate La₄Ni₃O_10-δ exhibits a nearly isotropic upper critical field under high pressure. This finding provides important experimental insight into the superconducting mechanism of nickel-based materials.

The study is published in Physical Review X.

Since the discovery of superconductivity with a transition temperature (T_c) approaching 80 K under high pressure in the bilayer Ruddlesden–Popper (RP) nickelate La₃Ni₂O_7-δ, bulk superconductivity (T_c≈20 K) has also been verified in single crystals of the trilayer isostructural compound La₄Ni₃O_10-δ under pressure. However, probing its properties remains technically demanding, as experiments must simultaneously achieve ultra-high pressure, strong magnetic fields and cryogenic temperatures.