Imaging magnetic order in a two-dimensional iron-rich phyllosilicate.

Magnetic domain formation in two-dimensional materials offers insight into the fundamentals of magnetism and serves as a catalyst for the advancement of spintronics. In order to propel these developments, it is crucial to acquire an understanding of the evolution of magnetic ordering at the nanometer scale. In particular, two-dimensional magnetic insulators allow for the realization of atomically sharp magnetoresistive tunneling junctions with nonmagnetic electrodes, therefore lifting one of the major constraints for the realization of computing in memory based on magnetoresistive elements. In this study, we visualize magnetic ordering in monolayers of annite, a fully air-stable layered magnetic mica. Using a nanometer-scale scanning superconducting quantum interference device microscopy, we directly observe domain formation in this representative of two-dimensional magnetic phyllosilicates.