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Ground state investigations of Ce and U intermetallic compounds
Bartha, Attila ; Prokleška, Jan (advisor) ; Detlefs, Blanka (referee) ; Michor, Herwig (referee)
Title: Ground state investigations of Ce and U intermetallic compounds Author: Attila Bartha Department: Department of Condensed Matter Physics Supervisor: RNDr. Jan Prokleška, Ph.D., Department of Condensed Matter Physics Abstract: Rare earth and actinide intermetallic compounds offer a plethora of interesting physical properties due to the varied behavior of f -electrons together with numerous interactions these electrons are exposed to. In this thesis we address a broad spectrum of ground state investigations on CePd2X3 (X=Zn, Ga) and (Ce,U)nTIn3n+2 (T=Rh, Ir) compounds. Single crystals of CePd2Zn3 and CePd2Ga3 compounds were synthesized for the first time using Bridgman method. CePd2Ga3 revealed a ferromagnetic transition with TC = 6.7 K with a strong magnetocrystalline anisotropy. CePd2Zn3 orders antiferromagnetically below TN = 1.9 K. Results of magnetization measurements on Ce2IrIn8 revealed effective magnetic moment µeff = 2.45µB/Ce3+ and a paramagnetic Curie temperature θP = −31 K. Decomposition of Hall resistivity ρxy(B) into NHE and AHE revealed a predom- inance of AHE in the temperature range from 60 K up to 100 K. Ce2RhIn8 was studied by means of magnetic field and angle dependent magnetization and heat capacity measurements. The resulting phase diagram reveals a complete unfold- ing and...
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The ground-state properties of new (RE, U) nTIn3n+2 intermetallic compounds
Kratochvílová, Marie ; Custers, Jeroen (advisor) ; Abd-Elmeguid, Mohsen (referee) ; De Boer, Frank Roelof (referee)
The ground-state properties of f-electron compounds are characterized by strong interactions which lead to a plethora of exotic states. In this thesis we focused on compounds crystallizing in the tetragonal HonCoGa3n+2-type structure. Several new compounds have been synthesized from In-flux; particularly enigmatic are Ce3TIn11 (T = Pd, Pt). These compounds possess two inequivalent Ce-sites and reveal coexistence of antiferromagnetic order and heavy fermion superconductivity at ambient pressure. This coexistence can be explained in the framework of two-Kondo ion lattice model, assuming one Ce-site being completely Kondo screened with the 4f-electron behaving itinerant and participating in superconductivity while the second Ce-site retains its local character giving rise to magnetic order via the RKKY interaction. The influence of crystal electric field on the magnetic ground state has been investigated on the Kondo compound Ce2RhIn8 by means of neutron experiments. U2RhIn8 and URhIn5 behave like transition-metal antiferromagnets, contrary to Ce(4f)-counterparts. The 5f-states are entirely hybridized and Kondo interactions play no role. Neither does it in the investigated RE2CoIn8 (RE = Pr, Nd, Dy) compounds which exhibit strong localized 4f-electron behavior. Here, the influence of strong...
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