posted on 2022-12-22, 13:03authored byAdam O’Neill, Sharidya Rahman, Zhen Zhang, Peggy Schoenherr, Tanju Yildirim, Bo Gu, Gang Su, Yuerui Lu, Jan Seidel
Emergent magnetism in van der Waals materials offers
exciting opportunities
in fabricating atomically thin spintronic devices. One pertinent obstacle
has been the low transition temperatures (Tc) inherent to these materials, precluding room temperature applications.
Here, we show that large structural gradients found in highly strained
nanoscale wrinkles in Cr2Ge2Te6 (CGT)
lead to significant increases of Tc. Magnetic
force microscopy was utilized in characterizing multiple strained
CGT nanostructures leading to experimental evidence of elevated Tc, depending on the strain percentage estimated
from finite element analysis. Our findings are further supported by ab initio and DFT studies of the strained material, which
indicates that strain directly augments the ferromagnetic coupling
between Cr atoms in CGT, influenced by superexchange interaction;
this provides strong insight into the mechanism of the enhanced magnetism
and Tc.