JRP 06-10
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ContactDr. J.C. GriveauInstitute for TransUranium elements, P.O Box 2340, D-76125 Karlsruhe, Germany  
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Critical behaviour of actinide compounds under high pressureStatus
GoalsThe project is focused on the high pressure-investigation for reaching the quantum criticality in the AnT2 Si2 (An = U, Pu, Np, T – transition metal) intermetallics. The ambient-pressure data show the variation of the magnetic ordering from the ferromagnetic (FM) to antiferromagnetic (AFM), and finally – to paramagnetic (PM) within the AnFe2Si2 (An = Pu, Np, U) series, and from the uncompensated AFM to AFM and to PM – within the UT2Si2 (T =Ni, Co, Fe) series. The high pressure-studies of these compounds would provide the information about the role of the f-f and f-d exchange interactions in the magnetic ordering mechanism. The application of the uniaxial stress would help to distinguish between the contributions from the different exchange types. Additional merit comes from the possibility to change both the d-element and f-element in AnT2Si2. We expect to observe the pressuredriven modification of the magnetic ordering type followed by the collapse of magnetism within the both series. Expected resultsThe primary investigation tool would be the measurements of the electrical resistivity under hydrostatic pressure as high as P = 20 GPa since it is the major experimental technique available for this pressure range. The technique to reach such high-pressure has been developed at ITU and the project would then involve the transfer of the high-pressure resistivity measurement technique from the EC-JRC-ITU to ILT&SR PAS and CUNI. CUNI will share the knowledge about the uniaxial stress methods as well as the application of the closed-cycle cryosystems for the high-pressure measurements. Once the high-pressure measurement techniques are established in all 3 groups, an actinide high-pressure pooled facility will be available to expand the scope of the project to further actinide compounds and materials. Reports |
