Hydrostatic pressure influence on T C in (Ga,Mn)As

The influence of hydrostatic pressure on the Curie temperature T-C of thin ferromagnetic (Ga,Mn)As layers is studied. New experimental data unambiguously point to both positive and negative pressure-induced changes of Curie temperature. The positive pressure coefficient is observed for samples with relatively high values of T-C and can be quantitatively described by the p-d Zener model of carrier-mediated ferromagnetism within the six-band k . p formalism and the ab initio approach. First-principles calculations of structural, electronic, and magnetic properties of (Ga,Mn)As show that antiferromagnetic coupling of substitutional Mn atoms with interstitial ones may account for a decrease of T-C under pressure in samples having a substantial concentration of interstitial Mn.