Large flexomagnetic response enabled by topological magnetic textures in monolayer CrN

Flexomagnetism refers to the interplay of strain gradient and magnetization, but intrinsic flexomagnetic effect is usually weak due to the symmetry breaking inconsistency between ferromagnetism related time reversal and strain gradient related space reversal. Herein we demonstrate a large flexomagnetic response in monolayer CrN by applying a constant strain gradient, and thus achieve a macroscopic flexomagnetic coefficient around $250\phantom{\rule{0.16em}{0ex}}{\textmu{}}_{\text{B}}\AA{}$ that is two orders of magnitude higher than the previously reported intrinsic value (in the order of $1\phantom{\rule{0.16em}{0ex}}{\textmu{}}_{\text{B}}\AA{}$). The large flexomagnetic response is found to be enabled by the strain gradient manipulation of Dzyaloshinskii-Moriya interaction (DMI), and thus the associated topological magnetic textures. It is revealed that a shear-strain gradient can effectively regulate DMI strength and modulate the topological magnetic textures including N\'eel-type skyrmion size/shape, domain walls, and magnetic domains in monolayer CrN. Our results could inspire the exploration of flexomagnetism using the strain-gradient engineering of topological magnetic textures in monolayers instead of multilayers.