LAUSR

We report the effect of chemical pressure on the ferromagnetic ordering of the recently reported n-type diluted magnetic semiconductor Ba(Zn[Formula: see text]Co[Formula: see text])[Formula: see text]As[Formula: see text] which has a maximum [Formula: see text] [Formula: see text] 45 K. Doping Sb into As-site and Sr into Ba-site induces negative and positive chemical pressure, respectively. While conserving the tetragonal crystal structure and n-type carriers, the unit cell volume shrink by [Formula: see text] 0.3[Formula: see text] with 15[Formula: see text] Sr doping, but drastically increase the ferromagnetic transition temperature by 18[Formula: see text] to 53 K. Our experiment unequivocally demonstrate that the parameters of Zn(Co)As[Formula: see text] tetrahedra play a vital role in the formation of ferromagnetic ordering in the Ba(Zn,Co)[Formula: see text]As[Formula: see text] DMS.