As magnetic materials approach their Curie temperature (Tc), they exhibit critical behavior, including divergent susceptibilities, long-range correlations, and spin dynamics across a wide frequency range. However, capturing these effects at the relevant length and time scales has remained challenging.

In research led by Benjamin Lawrie at Oak Ridge National Lab, scientists used NV relaxometry on the Qnami ProteusQ system to investigate a high-Tc ferromagnetic oxide near its phase transition. Their analysis of nanoscale magnetic textures identified a 3D universality class for static correlations, while optical relaxometry suggested an XY universality class for spin dynamics.

These findings provide new insights into phase transitions in magnetic materials and demonstrate the potential of scanning NV magnetometry for exploring critical phenomena at the nanoscale.