  Two-dimensional (2D) layered magnets, such as iron chalcogenides, have
emerged these years as a new family of unconventional superconductor and
provided the key insights to understand the phonon-electron interaction and
pairing mechanism. Their mechanical properties are of strategic importance for
the potential applications in spintronics and optoelectronics. However, there
is still lack of efficient approach to tune the elastic modulus despite the
extensive studies. Herein, we report the modulated elastic modulus of 2D
magnetic FeTe and its thickness-dependence via phase engineering. The grown 2D
FeTe by chemical vapor deposition can present various polymorphs, i.e.
tetragonal FeTe (t-FeTe, antiferromagnetic) and hexagonal FeTe (h-FeTe,
ferromagnetic). The measured Young's modulus of t-FeTe by nanoindentation
method showed an obvious thickness-dependence, from 290.9+-9.2 to 113.0+-8.7
GPa when the thicknesses increased from 13.2 to 42.5 nm, respectively. In
comparison, the elastic modulus of h-FeTe remains unchanged. Our results could
shed light on the efficient modulation of mechanical properties of 2D magnetic
materials and pave the avenues for their practical applications in nanodevices.
