- Petr Doležal: Structural Properties of (Ce,La)Pd2Al2-x¬Gax Compounds
- 11. 4. 2018, 14:30
- lecture room F2, first floor Ke Karlovu 5
- more information
Abstract:
Study of magnetic excitations in intermetallic compounds based on theory of crystal electric field is sufficient for most of rare-earth intermetallic compounds. But there are some compounds which do not fulfil this scheme. CeAl2, CeCuAl3 and CePd2Al2 are the examples of Ce based compounds. The observed results on these materials were explained in literature by the coupling of lattice vibrations to the crystalline electric field and formation of a “bound state” [1,2]. Our study is focused on CePd2Al2 and the series of (Ce,La)Pd2Al2-xGax compounds from structural point of view.
All the Ce,La)Pd2Al2-xGax compounds undergo a structural phase transition at low temperatures to the orthorhombic structure described within the Cmme space group. We studied the concentration dependence of the transition temperature (Tstr) by using the low temperature X-ray powder diffraction. Although all the parent ternary compounds should have the same structure at room temperature [2, 3], the character of their structure phase transition is considerably different.
We also studied the structure transition on a LaPd2Al2 single crystal and observed evidences of the formation of orthorhombic domains at temperatures below Tstr.
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[2] Chapon L. C., et al., Physica B 378–380 (2006) 819–820
[3] J. Kitagawa, et al., J. Phys. Soc. Jap., 2380-2383, 68 (1999).