Jan Prokleška: Magnetism, magnetic phase transitions and magnetic phase diagrams
Begin: 22.05.2019, 14:10
Location: lecture room F2, first floor Ke Karlovu 5

Title: Jaroslav Valenta:Evolution of magnetic phase diagram of UIrSi3 upon application of pressure
Number: 34/19
Status: Closing date exceeded
Begin: Středa, 17.04. 2019, 14:10
Tutor: Vladimír Sechovský
Location: lecture room F2, first floor Ke Karlovu 5

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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)




Evolution of magnetic phase diagram of UIrSi3 upon application of pressure

lecture given by:

Jaroslav Valenta


Charles University, Faculty of Mathematics and Physics, DCMP,
Ke Karlovu 5, 121 16 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, 17. 4. 2019 from 14:10 

Vladimír Sechovský
On behalf of the DCMP and MGML


The UIrSi3 compound is the Ising-like non-centrosymmetric antiferromagnet crystallizing in the tetragonal BaNiSn3-type crystal structure [1]. The magnetization and specific heat measurements performed on the single crystal sample revealed strong uniaxial anisotropy below TN = 41.7 K and easy magnetization direction along c-axis. Application of external magnetic field along the crystallographic c-axis suppresses the antiferromagnetic order at HC = 7.3 T. The first order metamagnetic transition exhibits asymmetric hysteresis at HC. The hysteresis narrows with increasing temperature and vanishes around 28 K. At higher temperatures a second order metamagnetic transition is observed up to TN [2]. Measurements of other physical quantities show unequivocally different character of first-order and second-order metamagnetic transition. These different characters of magnetic phase transitions are separated by a tricritical point appearing around 28 K at 5.6 T. The above mentioned resul
ts bear witness about complex AF ground-state magnetic structure which originates in the competition of ferromagnetic and antiferromagnetic exchange interactions. Application of hydrostatic pressure causes shift of the Néel temperature to higher temperatures whereas the critical field of metamagnetic transition decreases with increasing pressure. Generally, application of high pressure causes increasing overlap of 5f-wave functions leading to suppression of itinerant U magnetic moment and therefore decreasing of the Néel temperature is expected above certain pressure. Nevertheless, the opposite evolution of HC and TN promises the shift of the tricritical point to low magnetic fields and higher temperatures. Results from the measurements with application of pressure up to 6 GPa will be presented in the context of magnetic exchange interactions.

[1] B. Buffatet al., J. Magn. Magn. Mat.62, 53-56 (1986)
[2]J. Valenta, F. Honda, M. Vališka, P. Opletal, J. Kaštil, M. Míšek, M. Diviš, L. Sandratskii, J. Prchal, and V. Sechovský, Phys. Rev. B 97, 144423

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