Dr Jaco Olivier and Prof Jan Neethling from the Centre for High Resolution Transmission Electron Microscopy (TEM) at the Nelson Mandela University in Port Elizabeth are celebrating their recent publication in the prestigious Nature Materials*. The paper has caused quite a stir in the scientific community, with a commentary in Nature Materials news & views** and over one thousand views on LinkedIn. This is a true testament to the success of a multimillion rand DST/NRF investment which lead to the establishment of the Centre for HRTEM in October 2011.
The paper*, entitled Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond, is the result of collaboration between scientists at the Centre for HRTEM and scientists at the University of the Free State, Wits University, Oxford University, JEOL UK and the Max Planck Institute for Solid State Research. Defects in diamond are of interest because of their effect on the optical and electrical properties of diamond which has sought after applications in fields such as quantum computing. According to Professor Jannik Meyer** from the Physics of Nanostructured Materials Group at the University of Vienna, Austria, the paper has finally determined the structure of the platelet defect in diamond which has been “subject to a significant controversy for more than half a century”. Prof. Meyer went on to say that the “work of Olivier and colleagues is a remarkable step forward for characterizing this challenging material, and it also highlights a promising avenue to study defects in diamond where the identification of the platelet structure can be seen as a starting point”.
By using high resolution transmission electron microscopy and microstructure simulation techniques, Olivier and colleagues succeeded in matching the structure of the platelet defect in diamond to the zigzag structure of Barry and co-workers proposed in 1985 (see Figure below). This work has solved a 70 year old debate; and in so doing has opened new doors for “uncovering the vast zoo of defects with unknown structures”** in diamond.
|Figure Caption: Qualitative comparison of high resolution images of two platelets (A and B) to simulations of selected platelet models [Olivier EJ, Neethling JH, Kroon RE, Naidoo SR, Allen CS, Sawada H, van Aken PA and Kirkland AI Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond Nature Materials 17, 243–248 (2018)].|
This step forward in the microstructural characterisation of defects is the result of advances in aberration corrected microscopy. Modern high resolution microscopes have unprecedented resolving power and allow for the direct viewing of the atomic structure of materials. Without the double aberration corrected atomic resolution microscope at the Centre for HRTEM, South African scientists would not have had the infrastructure necessary to perform such cutting-edge research.
The DST/NRF-funded Centre for HRTEM was established in 2011 with the main aim of providing the enabling equipment infrastructure and expertise for nanoscale materials research and innovation in the country. Additional financial contributions came from the Nelson Mandela University, Sasol, the Department of Higher Education and Training and GHO Ventures in the USA. The establishment of the Centre was in response to the urgent need for an advanced electron microscopy facility in South Africa, coupled with the need to develop human capacity skilled in the use and interpretation of modern TEM. Such a facility is vital to support technology development and innovation in-line with national imperatives such as minerals beneficiation, the transformation towards a knowledge-based economy, energy security and the support of long-term nanoscience research.
Since its launch in October 2011, the Centre for HRTEM has established itself as a leading international research facility, and is the leading facility for advanced microscopy on the African continent. By combining state-of-the-art facilities with extensive local and international networks with leading industrial partners and universities, the Centre for HRTEM supports research in strategic areas such as power plant materials (including steels and ceramics used in nuclear power plants, and steels used in coal-fired power plants), nanoparticle catalysts, polycrystalline diamond compacts and other ultra-hard materials used in cutting and drilling tools, and platinum and titanium alloys as part of minerals beneficiation. Current collaborators include Sasol; Eskom; Hulamin; the DST-NRF Centre of Excellence in Strong Materials at the University of the Witwatersrand; the DST-NRF Centre of Excellence in Catalysis at the University of Cape Town; the Mechanical Engineering Departments at the Nelson Mandela University, Stellenbosch and UCT; the Russian Joint Institute for Nuclear Research; Element Six in the UK and in South Africa; The Ohio State University, Idaho National Laboratory and Westinghouse in the USA; Oxford University, the University of Manchester and King’s College London in the UK; the Max Planck Institute in Stuttgart, Germany; and the University of Linköping in Sweden.
For more information about the Centre for HRTEM and its services, visit chrtem.mandela.ac.za or contact Marisa Kolver on 041-504 4283.
*Olivier EJ, Neethling JH, Kroon RE, Naidoo SR, Allen CS, Sawada H, van Aken PA and Kirkland AI Imaging the atomic structure and local chemistry of platelets in natural type Ia diamond Nature Materials 17, 243–248 (2018)
**Meyer J Diamond Platelet Structure: Resolving the controversy Nature Materials 17, 210–211 (2018)