Negative thermal expansion of Ni-doped MnCoGe around room temperature - magnetic tuning
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Date
2019-02-05
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Institute of Physics
Abstract
Several materials have been shown to exhibit abnormal contraction with increasing temperature; the phenomenon of negative thermal expansion (NTE). Given this special property, NTE materials fulfill important functions in many modern technologies, such as electrodes of fuel cell, organic light-emitting diode (OLED), optical fibre, as well as high precision electronics and optical mirrors. In general, Nate properties are associated with local structural distortions or phase transitions, such as transverse phonon vibration in rigid unit modes, exile network of metal-organic framework, charge transfer, magneto-volume effect, ferroelectric transition, as well as displacive phase transition. Control or manipulation of Nate properties have become topics of increasing importance over the past two decades. Effective methods to produce materials with Nate properties include chemical doping, nanostructuralization, hydration and applied pressure. Recently, MoCoGe-based compounds were considered as a group of materials that exhibit giant NTE, with this behaviour attributed to the displacive martensitic phase transformation. In this investigation, we reported a new method to manipulate the NTE properties using applied magnetic fields. It is found that doping of 5% Ni on the Mn site could bring about a magneto-structural (MS) coupling in MnCoGe-based compounds. Magnetic-field-dependent neutron diffraction measurements demonstrated that an 8 T magnetic field could suppress the NTE by 31% at 295 K through this MS coupling.
Description
Keywords
Coupling, Doped materials, Magnetic fields, Magnetic properties, Materials, Nickel, Phase transformations, Temperature dependence, Thermal expansion
Citation
Ren, Q., Hutchison, W., Wang, J., Studer, A., Wang, G., .Zhou, H., Ma, J, & Campbell, S. (2019). Negative thermal expansion of Ni-doped MnCoGe around room temperature - magnetic tuning. Poster presented to the 43rd Annual Condensed Matter and Materials Meeting Charles Sturt University, Wagga Wagga, NSW 5th February - 8th February, 2019, (pp. 90). Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2019/Wagga_2019_Conference_Handbook.pdf