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Magnetic properties of R2TIn8 and related tetragonal compounds
Čermák, Petr ; Javorský, Pavel (advisor) ; Isnard, Olivier (referee) ; Honda, Fuminori (referee)
Title: Magnetic properties of R2TIn8 and related tetragonal compounds Author: Petr Čermák Department / Institute: Department of Condensed Matter Physics Supervisor of the doctoral thesis: doc. Mgr. Pavel Javorský, Dr., Department of Condensed Matter Physics Abstract: Intermetallic compounds R2TIn8 (R = rare earth, T = transition metal), commonly called "218" because of stoichiometry, are structurally related to a class of well- known Ce-based heavy-fermions like CeCoIn5 or CeRhIn5. They are located between fully 3D cubic compound (e.g. CeIn3) and quasi-2D "115" superconductors, which makes them ideal candidates to study structural dimensionality effects on various properties. Recent developments in this field showed that it is possible to grow compounds with T = Pd or Pt with "218" stoichiometry. Therefore further study of "218" compounds is desired since much less is known about them compared to "115" compounds. We have focused mainly on the determination of magnetic structures and crystal field effects along the series of Rh based "218" compounds for various rare-earth elements. The single crystals of compounds with R = Nd, Tb, Dy, Ho, Er, Tm, La, Lu, Y were successfully grown. Results of bulk measurements (specific heat, susceptibility) together with magnetic structures determined from several neutron...
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Magnetism in non-centrosymmetric uranium compound: UIrSi3
Valenta, Jaroslav ; Prchal, Jiří (advisor) ; Halevy, Itzhak (referee) ; Isnard, Olivier (referee)
Title: Magnetism in the non-centrosymmetric uranium compound: UIrSi3 Author: RNDr. Jaroslav Valenta Department: Department of Condensed Matter Physics Supervisor of the doctoral thesis: RNDr. Jiří Prchal, Ph.D., DCMP Abstract: The study presented in this thesis is focused on UIrSi3 which is one of two known uranium compounds that crystallize in a non-centrosymmetric structure. This first study of UIrSi3 in single-crystalline form confirms antiferromagnetic order below TN = 41.7 K and reveals strong uniaxial anisotropy. The antiferromagnetic order is suppressed by application of a magnetic field along the c axis (0HC = 7.3 T at 2 K). In contrast, application of a magnetic field up to 14 T along the a axis gives paramagnetic response. The high TN, contrasting with the low 0HC, together with the opposite signs of the paramagnetic Curie temperatures of the a-axis and c-axis paramagnetic susceptibility indicate a competition between antiferromagnetic and ferromagnetic interactions. The first-order metamagnetic transition at HC shows asymmetric hysteresis which reflects a complex antiferromagnetic ground state. With increasing temperature, the hysteresis becomes gradually smaller and vanishes at 28 K where the first-order transition changes to second-order transition which remains up to TN. The point where the...
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Magnetic properties of R2TIn8 and related tetragonal compounds
Čermák, Petr ; Javorský, Pavel (advisor) ; Isnard, Olivier (referee) ; Honda, Fuminori (referee)
Title: Magnetic properties of R2TIn8 and related tetragonal compounds Author: Petr Čermák Department / Institute: Department of Condensed Matter Physics Supervisor of the doctoral thesis: doc. Mgr. Pavel Javorský, Dr., Department of Condensed Matter Physics Abstract: Intermetallic compounds R2TIn8 (R = rare earth, T = transition metal), commonly called "218" because of stoichiometry, are structurally related to a class of well- known Ce-based heavy-fermions like CeCoIn5 or CeRhIn5. They are located between fully 3D cubic compound (e.g. CeIn3) and quasi-2D "115" superconductors, which makes them ideal candidates to study structural dimensionality effects on various properties. Recent developments in this field showed that it is possible to grow compounds with T = Pd or Pt with "218" stoichiometry. Therefore further study of "218" compounds is desired since much less is known about them compared to "115" compounds. We have focused mainly on the determination of magnetic structures and crystal field effects along the series of Rh based "218" compounds for various rare-earth elements. The single crystals of compounds with R = Nd, Tb, Dy, Ho, Er, Tm, La, Lu, Y were successfully grown. Results of bulk measurements (specific heat, susceptibility) together with magnetic structures determined from several neutron...
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