Transition metal (TM) doped ZnO is a promising diluted magnetic semiconductor (DMS) material for the
fabrication of spintronics devices. In this paper, we have investigated Mn and Cr doped ZnO thin films grown by RF
magnetron sputtering. The films grown on Si(100) and sapphire (Al<sub>2</sub>O<sub>3</sub>) have been characterized by X-ray diffraction
(XRD) and Vibrating Sample Magnetometer (VSM) to know its structural and magnetic properties. The XRD results
show that the Mn doped ZnO films deposited on Si (100) exhibit a polycrystalline nature whereas the films on sapphire
substrate have only (002) preferential orientations indicating that the films are single crystalline. It has been observed
from VSM studies that Zn<sub>1-x</sub>Mn<sub>x</sub>O/Al<sub>2</sub>O<sub>3</sub>(0001) and Zn<sub>1-x</sub>Cr<sub>x</sub>O/Si(100) system shows ferromagnetic nature while the
paramagnetic behaviour observed in Zn<sub>1-x</sub>Mn<sub>x</sub>O/Si(100) system.