  Two-dimensional (2D) layered materials possess outstanding mechanical,
electronic and optical properties, making them ideal materials for
nanoelectromechanical applications. The recent discovery of 2D magnetic
materials has promised a new class of magnetically active nanoelectromechanical
systems (NEMS). Here we demonstrate resonators made of 2D CrI3, whose
mechanical resonances depend on the magnetic state of the material. We quantify
the underlining effects of exchange and anisotropy magnetostriction by
measuring the field dependence of the resonance frequency under a magnetic
field parallel and perpendicular to the easy axis, respectively. Furthermore,
we show efficient strain tuning of magnetism in 2D CrI3 as a result of the
inverse magnetostrictive effect using the NEMS platform. Our results establish
the basis for mechanical detection of magnetism and magnetic phase transitions
in 2D layered magnetic materials. The new magnetic NEMS may also find
applications in magnetic actuation and sensing.
