Nanomechanical probing and strain tuning of the Curie temperature in suspended Cr2Ge2Te6-based heterostructures

Abstract

Abstract Two-dimensional magnetic materials with strong magnetostriction are attractive systems for realizing strain-tuning of the magnetization in spintronic and nanomagnetic devices. This requires an understanding of the magneto-mechanical coupling in these materials. In this work, we suspend thin Cr 2 Ge 2 Te 6 layers and their heterostructures, creating ferromagnetic nanomechanical membrane resonators. We probe their mechanical and magnetic properties as a function of temperature and strain by observing magneto-elastic signatures in the temperature-dependent resonance frequency near the Curie temperature, T C . We compensate for the negative thermal expansion coefficient of Cr 2 Ge 2 Te 6 by fabricating heterostructures with thin layers of WSe 2 and antiferromagnetic FePS 3 , which have positive thermal expansion coefficients. Thus we demonstrate the possibility of probing multiple magnetic phase transitions in a single heterostructure. Finally, we demonstrate a strain-induced enhancement of T C in a suspended Cr 2 Ge 2 Te 6 -based heterostructure by 2.5 ± 0.6 K by applying a strain of 0.026% via electrostatic force.