ANSTO's research capabilities, led by the OPAL nuclear research reactor and associated instruments provide access to users investigating areas as diverse as materials, life sciences, climate change and mining/engineering.
Recent Results
Our first overseas users used Wombat to measure a particular variant of the common piezoelectric material PZT (lead zirconate titanate). The PZT was subjected to a cycling electric field, switching at rates of 1Hz to 1kHz. The data was acquired stroboscopically: each time the electric field switches on the detector is retriggedered, and up to 64 time bins were measured for each period. This time resolution is a way of probing the time response of the material. The electric field induces strain and domain switching effects, which show up as subtle changes in the position or intensities of the peaks.
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| Shows the shift in the 111 peak of PZT due to the induced strain of the electric field | Figure 2 shows the shift in intensities in the 02/200 peaks due to domain switching. |
Congratulations to Ross Whitfield and Jessica Hudspeth on their outstanding honours theses. Both are students of Darren Goossens at the ANU, and the photo shows the three of them exhibiting their work at the recent AANSS conference. Wombat data made an important contribution to both their honours projects.
Jessica's study of the crystal and magnetic structure LaCa2Fe308 and NdCa2Fe308 has been submitted for publication and she graduated with first class honours and the University Medal. Ross, whose work using Wombat to look at real time structural change in stainless steel during sintering is a previous "Wombat Highlight", graduated with first class honours.
Having obtained its operating licence Wombat invites now users for (friendly user) experiments. Ross Whitfield, an honours student with Darren Goossens at the Australian National University in Canberra, looked at sintering processes of steel using the vacuum furnace looked at sintering processes of steel using the vacuum furnace. The data (below) show clearly the appearance and disappearance of various phases over a ramp/hold/cooling cycle of several hours, with data taken at one minute intervals.
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| Figure 3: Magnetic diffaction data |
Furthermore, Wombat took its first magnetic diffraction data on Pr0.8Ln0.2Mn2Ge2, a sample provided by Stewart Campbell, University of New South Wales at the Australian Defence Force Academy. The substitution of Lu for Pr leads to a decrease in the lattice constants a, c and the unit-cell volume at room temperature with this contraction of the unit cell resulting in modifications of the Pr1-xLuxMn2Ge2 magnetic structures.
Four magnetic phase transitions - linked primarily with temperature-driven changes in the intralayer Mn-Mn separation distances - have been detected within the temperature range 4.5 – 550 K. The diffraction pattern below was taken in the temperature range 5 - 265 K, showing formation of the Fmi magnetic state below Tc/c = 192 K for Pr0.8Lu0.2Mn2Ge2.
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| Figure 4: Sample environment apparatus |
On Wombat the focus is on commissioning sample-environment apparatus and running real-time experiments.