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Really First Principles Calculations for CoF₃

100%

Radwanski R., Nalecz D., Krupska M., Piwowarczyk T., Ropka Z.

Acta Physica Polonica A

2015

vol. 127

issue 2

391-393

We have derived the low-energy electronic structure of CoF₃, originating from the strongly-correlated 3d⁶ system of the Co³⁺ ion, taking into account the crystal-field interactions, with a relatively weak trigonal distortion, and the relativistic spin-orbit interaction. We have calculated from really first-principles the relevant crystal-field interactions. With the discrete electronic structure for 3d electrons we have described the magnetic properties (the value of the magnetic moment and its direction). The moment direction is determined by the local off-octahedral trigonal distortion proving the single-ion origin of the magnetocrystalline anisotropy. We evaluated the orbital moment and the strength of spin interactions responsible for the formation of the magnetic state. Our studies indicate that calculations of the electronic structure of a 3d compound for the physically-adequate description of the magnetic properties has to be performed at the meV scale.

Superconductivity in U-T Alloys (T = Mo, Pt, Nb, Zr) Stabilized in the Cubic γ-U Structure

86%

Sowa S., Kim-Ngan N., Krupska M., Paukov M., Tkach I., Havela L.

Acta Physica Polonica A

2016

vol. 130

issue 2

521-526

Using ultrafast cooling (with the cooling rate up to 10⁶ K/s) helps to minimize the T-alloying concentration (T = Mo, Pt, Pd, Nb, Zr) necessary to retain the γ-U phase down to low temperatures. All investigated splat-cooled U-T alloys become superconducting with T_{c} in the range of 0.61-2.11 K. The bulk character of superconductivity can be concluded for some of the splats when comparing the specific-heat anomaly at T_{c} with the BCS theory prediction.

Study of Ti, V and Their Oxides-Based Thin Films in the Search for Hydrogen Storage Materials

73%

Tarnawski Z., Zakrzewska K., Kim-Ngan N.-T., Krupska M., Sowa S., Drogowska K., Havela L., Balogh A.

Acta Physica Polonica A

2015

vol. 128

issue 3

431-439

Thin film series consisting of Ti, V, TiO₂ and V₂O₅ layer with different layer geometries, sequences and thicknesses have been prepared by the sputtering technique. The hydrogen depth profile of selected films upon hydrogen charging at 1 bar and/or hydrogenation at pressure up to 102 bar was determined by using secondary ion mass spectrometry and nuclear reaction analysis using a N-15 beam. The highest hydrogen storage with a concentration up to 50 at.% was found in the pure Ti and Ti-contained layer, while it amounts to around 30% in the metallic Ti-V-Ni layer. Hydrogen can diffuse through the TiO₂ layer without accumulation, but can be stored in the VO₂ layer in some cases. Hydrogen can remove the preferential Ti orientation in the films and induce a complete transition of V₂O₅ into VO₂ in the films.

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3 Acta Physica Polonica A

1 2016

2 2015

3 Krupska M.

2 Havela L.

2 Sowa S.

1 Balogh A.

1 Drogowska K.

1 Kim-Ngan N.

1 Kim-Ngan N.-T.

1 Nalecz D.

1 Paukov M.

1 Piwowarczyk T.

1 Radwanski R.

1 Ropka Z.

1 Tarnawski Z.

1 Tkach I.

1 Zakrzewska K.

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Really First Principles Calculations for CoF₃

Superconductivity in U-T Alloys (T = Mo, Pt, Nb, Zr) Stabilized in the Cubic γ-U Structure

Study of Ti, V and Their Oxides-Based Thin Films in the Search for Hydrogen Storage Materials