Magnetic two-dimensional (2D) crystals were isolated about a decade ago, triggering a tremendous research activity worldwide. This colloquium raises a stiff question: what is really new about them? At first sight, they seem to be purer implementations of 2D spin models than traditional systems such as ultra-thin films. Yet, they partly realized their promises so far, and whether they give fresh perspectives on long-standing predictions in statistical physics is still an open question. Undoubtedly, they are uniquely amenable to electric-field effect, susceptible to mechanical deformation, and sensitive to moir\'{e}s, for example. They represent interesting platforms for exploring, challenging, or simply revisiting a wide range of phenomena in condensed matter magnetism. This colloquium intends to offer a critical, yet not necessarily skeptical, overview of the field, clarifying what we believe could be unique with 2D magnets, related quasi-2D van der Waals magnets, and their heterostructures.
@article{arxiv.2512.19417,
title = {Colloquium: A critique on van der Waals and two-dimensional magnets},
author = {Johann Coraux and Nicolas Rougemaille and Cedric Robert and Clément Faugeras and Andrès Saul and Benoît Grémaud and Luis Hueso and Félix Casanova and Aurélien Manchon},
journal= {arXiv preprint arXiv:2512.19417},
year = {2025}
}