Evidence of momentum dependent hybridization in Ce2Co0.8Si3.2

We studied the electronic structure of the Kondo lattice system Ce2Co0.8Si3.2 by angle-resolved photoemission spectroscopy (ARPES). The spectra obtained below the coherence temperature consist of a Kondo resonance, its spin-orbit partner and a number of dispersing bands. The quasiparticle weight related to the Kondo peak depends strongly on Fermi vectors associated with bulk bands. This indicates a highly anisotropic hybridization between conduction band and 4f electrons - V_{cf} in Ce2Co0.8Si3.2.Comment: 6 page

Próba oceny czynników determinujących jakość życia ludzi starszych mieszkających w środowisku wiejskim

Celem niniejszej pracy jest próba oceny czynników warunkujących poczucie jakości życia wśród mieszkańców wsi. Badanie zostało przeprowadzone w 2010 roku. Próba badana liczyła 115 osób. Wykorzystano samodzielnie opracowany kwestionariusz wywiadu (30 pytań). Objęto nim 71 kobiet i 38 mężczyzn (ogółem 109 osób) w wieku 65 lat i więcej, co stanowiło 94,8% wszystkich mieszkańców z trzech wsi w województwie łódzkim w tej grupie wieku. W analizie statystycznej danych zastosowano następujące miary: wskaźniki struktury, miary położenia dla cech mierzalnych: średnia arytmetyczna, modalna, mediana. W pracy dokonano oceny zależności pomiędzy zmiennymi za pomocą testu niezależności 2 na poziomie istotności α≤0,05, a w przypadku ich istnienia oceniono siłę takiego związku, wyliczając współczynnik C-Pearsona. Wyniki badania: 58 badanych (28 kobiet i 30 mężczyzn) – było w związku małżeńskim. Najczęściej (40,4%) osoby badane były umiarkowanie zadowolone ze swojej sytuacji materialnej. 79% respondentów nie mieszkało samotnie. 27% zamieszkiwało tylko z małżonkiem, 26% z małżonkiem i z rodziną oraz 26% z wnukami. Większość badanych osób (52%) uznało swój stan zdrowia za przeciętny. Wyniki uzyskane w powyższym badaniu wykazały, że jakość życia osób starszych jest zdeterminowana wieloma czynnikami, do których należą m.in.: stan zdrowia, sytuacja materialna, kontakty rodzinne. Osoby starsze oprócz tego, że często potrzebują pomocy rodziny, same również stanowią wsparcie dla bliskich. Na poziomie istotności α≤0,05 stwierdzono statystyczną zależność pomiędzy płcią a częstością korzystania z pomocy rodziny przez osoby starsze

Valence band of Ce2Co0.8Si3.2Ce_{2}Co_{0.8}Si_{3.2} and Ce2RhSi3Ce_{2}RhSi_{3} studied by resonant photoemission spectroscopy and FPLO calculations

This work presents studies of the valence band of two Kondo lattice systems: Ce2Co0.8Si3.2, which is paramagnetic with the Kondo temperature T-K approximate to 50 K and Ce2RhSi3, which is antiferromagnetic below T-N = 4.5 K and exhibits TK approximate to 9 K. The photoemission spectra, which are obtained with photon energy tuned to Ce - 4d 4f resonance, reveal a Kondo peak at the Fermi energy (E-F), its spin orbit splitting partner at 0.24 eV and a broad maximum related to Ce f(0) final state. The spectra indicate that Kondo peak has a higher intensity for Ce2Co0.8Si3.2. The off-resonance photoemission data reveal that a maximum in the 3d electron density of states is shifted towards EF for Ce2Co0.8Si3.2 as compared to Ce2RhSi3. Full-potential local-orbital calculations were realized with local spin density approach +U approach for 213 stoichiometry. They show that a higher density of states near EF is observed for Ce2CoSi3. The calculations also reveal the existing tendencies for antiferromagnetic and ferromagnetic ground states in a case of Ce2RhSi3 and Ce2CoSi3, respectively

Ferromagnetic and spin-glass properties of single-crystalline U 2 NiSi 3

A single crystal of U 2 NiSi 3 was investigated by means of magnetization, electrical resistivity and heat capacity measurements. Whereas the DC magnetic data clearly manifest strongly anisotropic ferromagnetism, the AC magnetic susceptibility data are consistent with spin-glass behaviour, reported previously for polycrystalline samples. Moreover, no distinct anomalies around T C occur in the specific heat and electrical resistivity characteristics. Altogether the results obtained for single-crystalline U 2 NiSi 3 indicate rather an unusual state of coexistence of ferromagnetism and spin-glass freezing

Single-Crystal Growth of f-Electron Intermetallics in a Tetra-Arc Czochralski Furnace

The Czochralski technique has induced technological revolution in the electronic industry. It has also been widely used in the fundamental research area, as it allows obtaining high-quality single crystals of large variety of binary, ternary and multinary compounds. The unique tetra-arc Czochralski furnace installed at the Institute of Low Temperature and Structure Research, Polish Academy of Sciences in Wrocław, described in detail in the article, has been used to prepare a large number of single crystals of various Ce- and U-based intermetallic phases. Their excellent quality has facilitated advanced investigations of their anisotropic, often highly unusual physical properties

Ferromagnetism in structurally disordered UFe0.39Ge2

International audienceA polycrystalline sample of the uranium ternary germanide UFe0.39Ge2 was examined by means of X-ray powder diffraction, DC magnetization and AC magnetic susceptibility, heat capacity and electrical resistivity measurements performed in wide ranges of temperature and magnetic fields. The experiments confirmed that the compound crystallizes with orthorhombic crystal structure of the CeNiSi2-type that is closely re-lated to that of the ferromagnetic superconductor UGe2 and orders ferromagnetically at 37 K. Moreover, it exhibits some features characteristic of ferromagnetic cluster glasses. The electrical transport in UFe0.39Ge2 is strongly influenced by structural disorder arising from the partly occupied Fe-sites in its crystallographic unit cell. (C) 2021 The Author(s). Published by Elsevier B.V. CC_BY_NC_ND_4.

Quantum Interference in Disordered Ferromagnet U₂NiSi₃

A single-crystalline sample of disordered ferromagnetic U₂NiSi₃ was investigated by means of electrical resistivity measurements under ambient and high hydrostatic pressure. Temperature dependences of the electrical resistivity clearly reveal interplay of the ferromagnetic ordering and quantum interference effects resulting from crystallographic disorder. Electron-electron interaction manifests itself as a $T^{0.5}$ increase in the in-plane and out-of-plane electrical resistivity below 5 K. Weak localization is observed solely in the ab-plane as a linear-in-T contribution to resistivity, which suggests that internal magnetic field does not break the interference of scattered electron waves in ab-plane. Applied hydrostatic pressure does not affect the $T^{0.5}$ electron-electron interaction contribution, however it diminishes the impact of weak localization on the ab-plane resistivity