title: Enhancement of electrical and ferromagnetic properties by additional Al doping in Co:ZnO thin films.
abstract: Several properties of Al-doped Zn(0.95)Co(0.05)O thin films prepared by radio frequency (RF) magnetron co-sputtering have been systematically investigated. The experimental results indicate that Co(2+) steadily substitutes for tetrahedrally coordinated Zn(2+) in the ZnO wurtzite lattice without any segregated secondary phase formation, and that a trace amount of additional Al doping has a profound influence on the enhancement of electrical and magnetic properties of Co:ZnO films. All the films show room-temperature ferromagnetism, and a giant magnetic moment of 3.36 μ(B)/Co is obtained in the Zn(0.948)Co(0.05)Al(0.002)O thin film. The ferromagnetic ordering is seen to be correlated with the structural defects. Moreover, a phenomenon of band gap broadening and absorption edge blueshift can be achieved by additional Al doping into the Co:ZnO films.
authors.affiliation: Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: X J
authors.initials: XJ
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Song
authors.forename: F
authors.initials: F
authors.lastname: Zeng
authors.forename: F
authors.initials: F
authors.lastname: Pan