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Studium nových silně korelovaných elektronových sloučenin REnTIn3n+2
Bartha, Attila ; Kratochvílová, Marie (advisor) ; Pospíšil, Jiří (referee)
We have studied two different systems; RE2CoIn8 (RE = Pr, Nd, Dy) and CenTIn3n+2 (T = Pd, Pt; n = 2, 3). All compounds were prepared for the first time in the single crystalline form using the self-flux method. X-ray diffraction confirmed the tetragonal Ho2CoGa8 structure type for the RE2CoIn8 compounds and for the new phase Ce2TIn8. The novel phase Ce3PtIn11 adopts the structure of the Ce3PdIn11 compound, which represents a new structure type. Magnetic measurements revealed low anisotropy and the c-axis as the easy axis for all RE2CoIn8 compounds. Pr2CoIn8 is a paramagnet, while Nd2CoIn8 and Dy2CoIn8 order antiferromagnetically. Magnetization and specific heat measurements of Dy2CoIn8 revealed complex magnetic field-temperature phase diagram with various types of magnetic ordering. Specific heat measurements on multiphase Ce-Pd-In system revealed superconducting transition at Tc = 0.69 K arising from Ce2PdIn8 and another magnetic transition from Ce3PdIn11 at ~ 1.7 K. Ce3PdIn11 and Ce3PtIn11 compounds reveal two, probably magnetic transitions at T1 = 1.6 K, T2 = 1.45 K and T1 = 2.1 K and T2 = 2.0 K, respectively. Specific heat data qualifies both materials as heavy fermion compounds with γ = 290 mJ.mol-1 Ce K-2 and γ = 300 mJ.mol-1 Ce K-2 respectively.
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Studium magnetických a termodynamických vlastností ternárních sloučenin se silně korelovanými 4f elektrony.
Kratochvílová, Marie
We have studied two different systems of compounds, YPd2Al3 and CenTmIn3n+2m. Polycrystalline YPd2Al3, a new member of the REPd2Al3 system, was prepared by arc melting. The X-ray diffraction confirmed that YPd2Al3 crystallizes in the hexagonal PrNi2Al3-type structure as the other REPd2Al3 compounds. Magnetization, AC susceptibility, specific heat and resistivity measurements revealed superconductivity below Ts ≈ 2.2 K. The second part of the work was focused on studies of Ce2PdIn8 and Pd-doped CenRhIn3n+2. Single crystals of Ce2Rh1-xPdxIn8 with x = 0, 0.10, 0.15, 0.30, 0.45, 0.85, 1 and CeRh1-xPdxIn5 with x = 0, 0.1, 0.25 were prepared by solution growth method. The quality of crystals was confirmed by microprobe analysis and X-ray diffraction. The effect of Pd doping on magnetism of CenRh1-xPdxIn3n+2 was studied by specific heat, magnetization and resistivity measurements. The Pd doping gradually suppresses the Néel temperature in both systems, however the effect is stronger in Ce2Rh1-xPdxIn8. Temperature dependence of resistivity of CeRh0.75Pd0.25In5 was studied in pressure up to 2.2 GPa. Similar to CeRhIn5, the antiferromagnetism is gradually suppressed by the applied pressure, while superconductivity is induced and coexists with antiferromagnetism.
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Studium magnetických a termodynamických vlastností ternárních sloučenin se silně korelovanými 4f elektrony.
Kratochvílová, Marie
We have studied two different systems of compounds, YPd2Al3 and CenTmIn3n+2m. Polycrystalline YPd2Al3, a new member of the REPd2Al3 system, was prepared by arc melting. The X-ray diffraction confirmed that YPd2Al3 crystallizes in the hexagonal PrNi2Al3-type structure as the other REPd2Al3 compounds. Magnetization, AC susceptibility, specific heat and resistivity measurements revealed superconductivity below Ts ≈ 2.2 K. The second part of the work was focused on studies of Ce2PdIn8 and Pd-doped CenRhIn3n+2. Single crystals of Ce2Rh1-xPdxIn8 with x = 0, 0.10, 0.15, 0.30, 0.45, 0.85, 1 and CeRh1-xPdxIn5 with x = 0, 0.1, 0.25 were prepared by solution growth method. The quality of crystals was confirmed by microprobe analysis and X-ray diffraction. The effect of Pd doping on magnetism of CenRh1-xPdxIn3n+2 was studied by specific heat, magnetization and resistivity measurements. The Pd doping gradually suppresses the Néel temperature in both systems, however the effect is stronger in Ce2Rh1-xPdxIn8. Temperature dependence of resistivity of CeRh0.75Pd0.25In5 was studied in pressure up to 2.2 GPa. Similar to CeRhIn5, the antiferromagnetism is gradually suppressed by the applied pressure, while superconductivity is induced and coexists with antiferromagnetism.
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Studium nových silně korelovaných elektronových sloučenin REnTIn3n+2
Bartha, Attila ; Kratochvílová, Marie (advisor) ; Pospíšil, Jiří (referee)
We have studied two different systems; RE2CoIn8 (RE = Pr, Nd, Dy) and CenTIn3n+2 (T = Pd, Pt; n = 2, 3). All compounds were prepared for the first time in the single crystalline form using the self-flux method. X-ray diffraction confirmed the tetragonal Ho2CoGa8 structure type for the RE2CoIn8 compounds and for the new phase Ce2TIn8. The novel phase Ce3PtIn11 adopts the structure of the Ce3PdIn11 compound, which represents a new structure type. Magnetic measurements revealed low anisotropy and the c-axis as the easy axis for all RE2CoIn8 compounds. Pr2CoIn8 is a paramagnet, while Nd2CoIn8 and Dy2CoIn8 order antiferromagnetically. Magnetization and specific heat measurements of Dy2CoIn8 revealed complex magnetic field-temperature phase diagram with various types of magnetic ordering. Specific heat measurements on multiphase Ce-Pd-In system revealed superconducting transition at Tc = 0.69 K arising from Ce2PdIn8 and another magnetic transition from Ce3PdIn11 at ~ 1.7 K. Ce3PdIn11 and Ce3PtIn11 compounds reveal two, probably magnetic transitions at T1 = 1.6 K, T2 = 1.45 K and T1 = 2.1 K and T2 = 2.0 K, respectively. Specific heat data qualifies both materials as heavy fermion compounds with γ = 290 mJ.mol-1 Ce K-2 and γ = 300 mJ.mol-1 Ce K-2 respectively.
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Studium magnetických a termodynamických vlastností ternárních sloučenin se silně korelovanými 4f elektrony.
Kratochvílová, Marie ; Pospíšil, Jiří (advisor) ; Custers, Jeroen (referee)
We have studied two different systems of compounds, YPd2Al3 and CenTmIn3n+2m. Polycrystalline YPd2Al3, a new member of the REPd2Al3 system, was prepared by arc melting. The X-ray diffraction confirmed that YPd2Al3 crystallizes in the hexagonal PrNi2Al3-type structure as the other REPd2Al3 compounds. Magnetization, AC susceptibility, specific heat and resistivity measurements revealed superconductivity below Ts ≈ 2.2 K. The second part of the work was focused on studies of Ce2PdIn8 and Pd-doped CenRhIn3n+2. Single crystals of Ce2Rh1-xPdxIn8 with x = 0, 0.10, 0.15, 0.30, 0.45, 0.85, 1 and CeRh1-xPdxIn5 with x = 0, 0.1, 0.25 were prepared by solution growth method. The quality of crystals was confirmed by microprobe analysis and X-ray diffraction. The effect of Pd doping on magnetism of CenRh1-xPdxIn3n+2 was studied by specific heat, magnetization and resistivity measurements. The Pd doping gradually suppresses the Néel temperature in both systems, however the effect is stronger in Ce2Rh1-xPdxIn8. Temperature dependence of resistivity of CeRh0.75Pd0.25In5 was studied in pressure up to 2.2 GPa. Similar to CeRhIn5, the antiferromagnetism is gradually suppressed by the applied pressure, while superconductivity is induced and coexists with antiferromagnetism.
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