Enhancement of ferromagnetic properties in Zn1−xCoxO by additional Cu doping

Abstract

The high-temperature ferromagnetism in Co-doped ZnO samples fabricated by the standard solid-state reaction method is reported. Additional Cu doping into bulk Zn 0.98 Co 0.02 O is essential to achieve room-temperature ferromagnetism. Structure and composition analyses revealed that cobalt is incorporated into the lattice structure, forming a solid solution instead of precipitates. In the case of Zn 0.97 Cu 0.01 Co 0.02 O, the coercive field measured by a vibrating sample magnetometer at room temperature is 60 Oe. The implication of the effect of Cu doping in bulk Zn 0.98 Co 0.02 O is also discussed.

Hydrothermal synthesis of Co-doped ZnO flakes with room temperature ferromagnetism

“…Since there are no Co-related impurities contributing to the room temperature ferromagnetism in the Zn 1−x Co x O flakes, we believe that the observed ferromagnetism at room temperature is an intrinsic property of Co-doped ZnO flakes. The carrier-induced ferromagnetism [12,31,32] that is frequently reported in II-IV semiconductors as well as III-V semiconductor can be the other possible origin of ferromagnetism. In this mechanism, the free carrier concentration is vital to determine whether the material is paramagnetic or ferromagnetic.…”

Electronic and magnetic properties of Co-doped ZnO diluted magnetic semiconductor

“…While some researchers have attributed the observed RTFM to Co clustering [14][15][16][17], many others have claimed it to be of intrinsic nature [18][19][20][21][22][23]. In case of polycrystalline bulk samples, there are several reports of PM behaviour at 300 K [24][25][26][27]. However, the RTFM was claimed when the samples were either co-doped with CuO [25] or when they were hydrogenated [26,27].…”

“…In case of polycrystalline bulk samples, there are several reports of PM behaviour at 300 K [24][25][26][27]. However, the RTFM was claimed when the samples were either co-doped with CuO [25] or when they were hydrogenated [26,27].…”

A study of structural, optical and magnetic properties of Zn0.97−xCuxCr0.03O diluted magnetic semiconductors

“…Lin et al supposed that a small amount of additional Cu doping would create additional carriers in Co doping ZnO, and its magnetization would be greatly enhanced in bulk samples [20]. N. Brihi et al asserted that the anti-ferromagnetism of Zn 0.97 Mn 0.03 O polycrystalline increased after Al-doping [21].…”