Structural engineering of ferromagnetism in III–V digital ferromagnetic heterostructures

Abstract

We investigate the possibility of modulating the magnetic properties of (Ga,Mn)As digital ferromagnetic heterostructures (DFHs) via strain engineering. We p-dope DFHs below the compensation threshold of residual As antisites to achieve variations in strain without introducing free carriers and with relatively modest concentrations of impurity atoms. X-ray diffraction and superconducting quantum interference device measurements reveal a trend toward higher TC as the out-of-plane strain is increased. Additionally, we demonstrate a second method for strain engineering wherein DFHs are grown on anisotropically relaxed (Ga,In)As stressor layers. We show that the ferromagnetic properties are independent of strain in this regime and conclude that the structure-dependent modulation of magnetic properties in DFHs cannot be explained by simple strain effects alone.