Advanced Materials
The Advanced Materials group is actively engaged in the investigation of the properties and behaviour of materials with topics as diverse as:
- the phosphorus-in-silicon system as a potential basis for spin-based quantum computing
- fundamental properties of rare earth based intermetallics and compounds
- characterization of III-V semiconductors
- monitoring wear in prosthetic joints.
- phase analysis of ore refining processes
- sediment transport in river basins and local forests.
In most instances, atomic or nuclear probes are used to study the microscopic properties of the materials involved or their spectroscopic “fingerprints” are used to identify and quantify the amounts of materials and phases present.
The key nuclear probe techniques employed include Mössbauer spectroscopy (57Fe as well as rare earth resonances such as 169Tm, 161Dy) and the very low temperature techniques of Nuclear Orientation (NO) and Nuclear magnetic Resonance on Oriented Nuclei (NMRON). Perturbed angular correlation (PAC) measurements are conducted in collaboration with Prof. Aidan Byrne of the ANU, who was closely associated with the development of the joint radioisotope implanter that is sited here at ADFA. Where radioactive nuclei are employed, they are either diffused into the specimens or implanted using the radioisotope implanter. Sometimes they are activated in situ via neutron irradiation at the Lucas Heights reactor facility. The process of ion implantation is of interest in its own right and is investigated using our School's radioisotope implanter as well as in collaboration with researchers at other facilities.
The in-house atomic probe technique is that of pulsed and swept-field electron spin resonance (ESR). Although this facility was designed specifically for the quantum computing project, it opens up exciting new possibilities for the study of other dilute magnetic systems.
These microscopic techniques are used in combination with x-ray and neutron powder diffraction, inelastic neutron scattering, specific heat, and bulk DC magnetisation and AC susceptibility measurements.
Link to Advanced Materials Research Report 09/10 (pdf file)
NEW - Condensed Matter & Materials Website hosted by PEMS
Wayne Hutchison has a strong research background in magnetic resonance, in particular with regard to nuclear magnetic resonance (NMR), the very low temperature technique of NMR on oriented nuclei (NMRON) and, most recently, electron spin resonance (ESR).
First and foremost, he runs the magnetic resonance program as part of the Centre for Quantum Computer Technology (See http://www.qcaustralia.org). The general aim of this program is the application of magnetic resonance, directly, to measurements on spin systems which have application as spin based quantum computers (QC). The emphasis is on ESR studies of the phosphorus in silicon (Si:P) system. The technique is also applied to investigations of the principal materials and fabrication processes.
Another research interest is the experimental investigation of rare earth based intermetallic compounds, in particular the intriguing RNiAl4 series (R = rare earth). This involves a range of techniques from bulk magnetic measurements to low temperature nuclear orientation (LTNO) and neutron diffraction. A third project is the application of the millikelvin techniques of LTNO and NMRON to dilute magnetic alloys and magnetic insulating compounds with interesting very low temperature behaviour. In particular, he is presently exploring the application of the enhanced nuclear paramagnet, HoF3 as a magnetic refrigerant at very low temperatures. Wayne is also involved in a project to study ion beam synthesis and modification of nanostructures (crystals, wires and layers) .
Glen Stewart's background is in hyperfine interaction techniques and his current research is directed primarily at rare earth compounds that exhibit interesting bulk behaviour and/or potential for technological application. These properties are often influenced by the local crystal field and magnetic exchange interactions at the rare earth site. The key technique employed at UNSW@ADFA is that of 169Tm Mössbauer spectroscopy. The crystal field is characterized via the temperature-dependent quadrupole interaction that it induces at the 169Tm nucleus. Other rare earth Mössbauer resonances (including 155Gd, 166Er and170Yb) are available via international collaborations and the Mössbauer spectroscopy investigations are complemented by inelastic neutron scattering, magnetic susceptibility and specific heat measurements. Materials currently under investigation include multi-ferroic and colossal magnetoresistance rare earth manganites, the intermetallic silicides RT2 Si2 (R = rare earth, T = Cu, Ni, Co, Fe, Mn, Cr) and, in collaboration with Wayne Hutchison, the intermetallic series RNiAl4 which exhibits intriguing magnetic properties.
A concerted effort has also been directed at the application of 57Fe-Mössbauer spectroscopy as a tool for monitoring ore refining processes. Although many analysis techniques provide precise quantitative information on the relative amounts of elements, they cannot provide the chemical form in which these elements are present. This is where a phase analysis technique such as 57Fe-Mössbauer spectroscopy comes into its own, especially in sectors of the mining industry where iron-rich ores are involved.
Heiko Timmers has a strong research background in nuclear physics and is active in collaborative projects dealing with fusion dynamics and scattering and the sensitive technique of elastic recoil detection (ERD) as applied to the quantitative compositional depth-profiling of materials and thin films. He is responsible for the operation and continuing development of the joint UNSW@ADFA/ANU 155 keV radioisotope implanter which uses a versatile negative ion source. Implanted radioactive probes are employed to study the microscopic properties of materials via ultra-sensitive, hyperfine interaction spectroscopy techniques such as perturbed angular correlation (PAC) and NMR on oriented nuclei (NMRON).
Most recently, he is active in two separate collaborative projects that exploit the ability to detect very dilute concentrations of radioisotopes. The first of these uses radioisotope tracing to monitor sediment transport in large river basins and local forests. The second project measures the dynamics of wear debris shedding from knee prostheses with the unprecedented accuracy of rare isotope tracing and accelerator mass spectrometry.
(Emeritus Prof. Stewart Campbell)
Stewart Campbell has an impressive publication record in the broad fields of neutron scattering and 57Fe-Mössbauer spectroscopy. He is currently an Emeritus Professor with the Advanced Materials group and has recently been awarded the AINSE Gold Medal for Excellence in Research, 2007 by the Australian Institute of Nuclear Science and Engineering (http://www.ainse.edu.au/ainse.html ).
His present research activities involve magnetic phase diagrams, valence transitions and the interplay between the rare earth and transition metal sub-lattices in intermetallic compounds, the high energy milling process and structure-property relationships in nanoscale solids with respect to nanomagnetism, and critical magnetic behavior and giant magneto-caloric effects.
Members of the Advanced Materials Research Group
Academic Staff:
Dr Wayne Hutchison (w.hutchison@adfa.edu.au) BSc, PhD UNSW, MAIP, MVSA
Assoc. Prof. Glen Stewart (g.stewart@adfa.edu.au) BSc, PhD, DipEd. Monash, FAIP
Dr Heiko Timmers (h.timmers@adfa.edu.au) BSc Münster, MSc Munich, PhD ANU
Professorial Visiting Fellow:
Emeritus Prof. Stewart Campbell (s.campbell@adfa.edu.au) BSc Aberd., MSc Salf., PhD Monash, CPhys, FlnstP, FAIP
Research Associates:
Dr Laura Gladkis (l.gladkis@adfa.edu.au) BSc Argentina, PhD ANU
Dr Jianli Wang (j.wang@adfa.edu.au) BSc Shandong University, China, MSc, PhD Institute of Physics, Chinese Academy of Sciences
Research Students:
Anwaar Malik - Research Topic - Atomic-scale modifications of carbon clusters and nanotubes by ion radiation.
Banchachit Saensunon - Research Topic - The influence of crystal field interactions in rare-earth intermetallic compounds (submitted Sept 2009).
Hazar Salama - Research Topic - The structural and magnetic properties of rare earth manganites.
Nakorn Suwuntanasarn - Research Topic - Magnetic resonance studies of PiSi Qubits (submitted thesis Feb 2008).
Recent Graduate Student:
Santosh Kumar Shrestha - Research Topic - Characterisation of indium nitride films with swift ions and radioisotope probes, PhD Thesis, 2005.
Members of the Advanced Materials Group in front of the entrance to the School's South Building.
Back row (L to R): Dr Wayne Hutchison , Natasa Bulatovic, Anwaar Malik (PhD student), Dr Steve James (IT, computing). Middle row (L to R): Dr Heiko Timmers, Hazar Ali Salama (PhD student), Assoc. Prof. Glen Stewart. Front row (L to R): Nakorn Suwuntanasarn (PhD student), Emeritus Prof. Stewart Campbell, Banchachit Saensunon (PhD student).
Absent: Dr Laura Gladkis & Dr Jianli Wang (Research Associates).