Motaung, DEMhlongo, Gugu HNkosi, SSMalgas, GFMwakikunga, Bonex WCoetsee, ESwart, HCAbdallah, HMIMoyo, TRay, SS2014-09-222014-09-222014-05Motaung, D.E, Mhlongo, G.H, Nkosi, S.S, Malgas, G.F, Mwakikunga, B.W, Coetsee, E, Swart, H.C, Abdallah, H.M.I, Moyo, T and Ray, S.S. 2014. Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures. ACS Applied Materials & Interfaces, vol. 6(12), pp 8981-89951944-8244http://pubs.acs.org/doi/ipdf/10.1021/am501911yhttp://hdl.handle.net/10204/7680https://doi.org/10.1021/am501911yCopyright: 2014 ACS Publications. This is an ABSTRACT ONLY. The definitive version is published in ACS Applied Materials & Interfaces, vol. 6(12), pp 8981-8995We report on the room temperature ferromagnetism of various highly crystalline zinc oxide (ZnO) nanostructures, such as hexagonally shaped nanorods, nanocups, nanosamoosas, nanoplatelets, and hierarchical nano “flower-like” structures. These materials were synthesized in a shape-selective manner using simple microwave assisted hydrothermal synthesis. Thermogravimetric analyses demonstrated the as-synthesized ZnO nanostructures to be stable and of high purity. Structural analyses showed that the ZnO nanostructures are polycrystalline and wurtzite in structure, without any secondary phases. Combination of electron paramagnetic resonance, photoluminescence, and X-ray photoelectron spectroscopy studies revealed that the zinc vacancies (V(subZn)) and singly ionized oxygen vacancies (V(subO)(sup+) located mainly on the ZnO surface are the primary defects in ZnO structures. A direct link between ferromagnetism and the relative occupancy of the V(subZn) and V(subO((sup+) was established, suggesting that both V(subZn) and V(subO)(sup+) on the ZnO surface plays a vital role in modulating ferromagnetic behavior. An intense structure- and shape-dependent ferromagnetic signal with an effective g-value of >2.0 and a sextet hyperfine structure was shown. Moreover, a novel low field microwave absorption signal was observed and found to increase with an increase in microwave power and temperature.enZnOHydrothermal synthesisMorphologyMagnetic propertiesArticleMotaung, D., Mhlongo, G. H., Nkosi, S., Malgas, G., Mwakikunga, B. W., Coetsee, E., ... Ray, S. (2014). Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures. http://hdl.handle.net/10204/7680Motaung, DE, Gugu H Mhlongo, SS Nkosi, GF Malgas, Bonex W Mwakikunga, E Coetsee, HC Swart, HMI Abdallah, T Moyo, and SS Ray "Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures." (2014) http://hdl.handle.net/10204/7680Motaung D, Mhlongo GH, Nkosi S, Malgas G, Mwakikunga BW, Coetsee E, et al. Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures. 2014; http://hdl.handle.net/10204/7680.TY - Article AU - Motaung, DE AU - Mhlongo, Gugu H AU - Nkosi, SS AU - Malgas, GF AU - Mwakikunga, Bonex W AU - Coetsee, E AU - Swart, HC AU - Abdallah, HMI AU - Moyo, T AU - Ray, SS AB - We report on the room temperature ferromagnetism of various highly crystalline zinc oxide (ZnO) nanostructures, such as hexagonally shaped nanorods, nanocups, nanosamoosas, nanoplatelets, and hierarchical nano “flower-like” structures. These materials were synthesized in a shape-selective manner using simple microwave assisted hydrothermal synthesis. Thermogravimetric analyses demonstrated the as-synthesized ZnO nanostructures to be stable and of high purity. Structural analyses showed that the ZnO nanostructures are polycrystalline and wurtzite in structure, without any secondary phases. Combination of electron paramagnetic resonance, photoluminescence, and X-ray photoelectron spectroscopy studies revealed that the zinc vacancies (V(subZn)) and singly ionized oxygen vacancies (V(subO)(sup+) located mainly on the ZnO surface are the primary defects in ZnO structures. A direct link between ferromagnetism and the relative occupancy of the V(subZn) and V(subO((sup+) was established, suggesting that both V(subZn) and V(subO)(sup+) on the ZnO surface plays a vital role in modulating ferromagnetic behavior. An intense structure- and shape-dependent ferromagnetic signal with an effective g-value of >2.0 and a sextet hyperfine structure was shown. Moreover, a novel low field microwave absorption signal was observed and found to increase with an increase in microwave power and temperature. DA - 2014-05 DB - ResearchSpace DP - CSIR KW - ZnO KW - Hydrothermal synthesis KW - Morphology KW - Magnetic properties LK - https://researchspace.csir.co.za PY - 2014 SM - 1944-8244 T1 - Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures TI - Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures UR - http://hdl.handle.net/10204/7680 ER -