3d-transition-metal-doped ZnO films (n-type Zn1-xMxO (x=0.05-0.25): M=Co, M
n, Cr, Ni) are formed on sapphire substrates using a pulsed-laser depositio
n technique, and their magnetic and electric properties are examined. The C
o-doped ZnO films showed the maximum solubility limit. Some of the Co-doped
ZnO films exhibit ferromagnetic behaviors with the Curie temperature highe
r than room temperature. The magnetic properties of Co-doped ZnO films depe
nd on the concentration of Co ions and carriers. (C) 2001 American Institut
e of Physics.