同步輻射研究中心中子小組

Prof W.F. Pong, from Tamkang University in Taiwan, along with collaborators from ANSTO and Osaka University in Japan, published the first research paper from the cold neutron, triple axis spectrometer, Sika.  

Just published in the Physical Review B, Prof. Pong used the neutron Spectrometer at OPAL to investigate the spatial spin-spin correlations and the spin relaxation processes in a single crystal of (Ni_0.4Mn_0.6)TiO₃. 

The parent compounds of this solid solution are antiferromagnetic with orthogonal easy axes of magnetisation.  When mixed at this 40/60 ratio the long range magnetic order is supressed and a glassy magnetic groundstate is formed, possibly hosting magnetic texture, such as a skyrmion with possible technological applications for spintronics. 

Using Sika, the team worked on the dimensionality of the spin-spin correlations and the universality class of the spin system.  It was found that the spatial correlations are over three times greater in the plane than out, but the relaxation processes in the two directions were within experimental error of each other.

The full reference is “Correlations and dynamics of spins in an XY-like spin-glass (Ni_0.4Mn_0.6)TiO₃ single crystal system”, R. S. Solanki, S. -H. Hsieh, C. H. Du, G. Deng, C. W. Wang, J. S. Gardner, H. Tonomoto, T. Kimura and W. F. Pong

Phys. Rev. B 95, 024425 (2017)

DOI:https://doi.org/10.1103/PhysRevB.95.024425

On Friday the 12th of June, the Australian Radiation Protection and Nuclear Safety Agency has given approval to commence user and commercial operations on SIKA cold neutron triple axis spectrometer.

User experiments approved following the Program Advisory Committee meeting in May 2015 can now be scheduled.

This demonstrated our commitment to service for Taiwan neutron research.

The SIKA cold-neutron 3-axis spectrometer, which is operated by the NSRRC, has taken its first neutron scattering patterns.  A diffraction pattern of a common standard Ni was first measured in diffraction mode before the 3^rd axis was added to produce an inelastic neutron scattering spectrum of a crystal-field excitation in PrFeO₃. 

A fixed incident energy of 5.11 meV was used and the spectrum shows a scan of the final energy, with the excitation at an energy transfer of around 2 meV.