ABSTRACT
We report the ferromagnetism in a new bulk form Cu-based magnetic semiconductor (La,Ba)(Cu,Mn)SO, which is iso-structural to the prototypical iron-based 1111-type superconductor LaFeAsO. Starting from the parent compound LaCuSO, carriers are introduced via the substitutions of La for Ba while spins are introduced via the substitutions of Cu for Mn. Spins are mediated by carriers, which develops into the long range ferromagnetic ordering. The maximum Curie temperature [Formula: see text] reaches up to [Formula: see text] 170 K with the doping levels of 10% Ba and 5% Mn. By comparing to the (La,Sr)(Cu,Mn)SO where Sr and Mn are co-doped into LaCuSO, we demonstrate that negative chemical pressure would suppress the ferromagnetic ordering.
ABSTRACT
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.
