Oleksandra Koloskova: The impact of the hydrogenation on the physical properties and crystal structure of the splat-cooled U1-xVx alloys
Venue: lecture room F2, first floor Ke Karlovu 5
We have a pleasure to invite you to attend the joint seminar
of the Department of Condensed Matter Physics (DCMP)
and the Materials Growth and Measurement Laboratory (MGML) http://mgml.eu.
THE IMPACT OF THE HYDROGENATION ON THE PHYSICAL PROPERTIES AND CRYSTAL
STRUCTURE OF THE SPLAT-COOLED U1-xVx ALLOYS
lecture given by:
DCMP, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague 2, Czech Republic
The seminar takes place in the lecture room F2
of the Faculty of Mathematics and Physics, Ke Karlovu 5, Praha 2
on Wednesday, 30.10. 2019 from 14:10
On behalf of the DCMP and MGML
There exist a set of studies conducted on U-T (T – transition metal) splat-cooled alloys which revealed that ? -U is stabilized to low temperatures far beyond the thermal equilibrium in these systems . All of these compounds are weak Pauli paramagnets, often with a superconducting ground state. Vanadium was chosen as a new element for experiments as there is a lack of information about the U-V system physical properties. Unfortunately, we did not succeed in obtaining a single-phase splat-cooled sample as for the other U-T samples (like U-Mo or U-Zr). The bi-phase composition becomes obvious from the XRD study and the analysis of the resistivity slope.
However, it is known that hydrogenation can bring a homogenization into the system. It turned out that inserting hydrogen into the U-V alloy results in a completely different hydride-structure compared to previously investigated U-T systems. In particular, Zr alloying brings ?-UH3 and Mo alloying gives nanocrystalline (2 nm grain size) ß-UH3 type . Whereas, (UH3)-V samples turned out to have crystalline ß-UH3 structure. A similar increase in TC values (up to 190 K) compared to pure UH3 (165 K) is observed as for the other alloying elements. Summing up, the increase of the Curie temperature in regular crystalline ß-UH3 suggests that this has a fully electronic origin independent of any peculiarities in the crystal structure.
The crystal structure of splat-cooled and hydrogenated systems will be presented, as well as the information about the transport properties of the initial alloys and magnetic properties of the corresponding hydrides.
 N.-T.H. Kim-Ngan et al., J.Nucl.Mater. 479 (2016) 287-294.
 L. Havela et al., J.Mag.Mag.Mater. 400 (2016) 130-136.
- Wednesday, 30 October 2019 14:10 - 15:10