MGML

Materials Growth & Measurement Laboratory

Petr Doležal: Bound state of crystal electric field excitation and a phonon – CePd2Al2

Seminar on Magnetism
Date: Wednesday, 10 April 2019 14:10 - 15:10

Venue: lecture room F2, first floor, Ke Karlovu 5 - Prague 2

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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) http://mgml.eu.

 

Program


Bound state of crystal electric field excitation and a phonon - CePd2Al2

lecture given by:

Petr Doležal

Charles University, Faculty of Mathematics and Physics,
Department of Condensed Matter Physics,
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, 10.4. 2019 from 14:10

Vladimír Sechovský
On behalf of the DCMP and MGML

Abstract:

     The existence of a bound state (vibron state) between 4f electrons and phonons in the Ce intermetallic compounds was mentioned first during investigation of physical properties in cubic CeAl2 [1]. The Thalmeier-Fulde model of vibron state was developed to give an explanation for magnetic excitations in this compound [2]. For a long time CeAl2 was a unique compound in which this enhanced interaction was observed. The increasing interest in recent time is motivated by new tetragonal materials which exhibit similar behaviour: CePd2Al2 [3], CeCuAl3 [4] and CeAuAl3 [5]. The crucial point of the theory is the fact that all Ce ions in the compound have the same point group symmetry, which could not be always fulfilled in CeCuAl3, which form a solid solution.

     Our interest will be focused on CePd2Al2 and non-magnetic analogue LaPd2Al2 which crystalize in tetragonal CeBe2Ge2 structure type and undergo a structural phase transition decreasing its symmetry in the basal plane. The resulting structure can be then described within the orthorhombic Cmme space group. We succeeded with preparation of single crystalline (Ce,La)Pd2Al2 samples and investigated their phonon dispersion curves. The results will be discussed in terms of enhanced magneto-elastic interaction.

 

[1] Thalmeier P. et al., Phys. Rev. Lett. 49 (1982) 1588 – 1591

[2] Loewenhaupt M. et al., Phys. B 86-88 (1977) 187-188

[3] Chapon L. C. et al., Physica B 378–380 (2006) 819 - 820

[4] Adroja D. T. et al., Phys. Rev. Lett. 108 (2012) 216402

[5] Čermák P. et al., PNAS 14 (2019) 6695-6700

 

Address
Ke Karlovu 5, 121 16 Praha 2, Czech Republic

 

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All Dates


  • Wednesday, 10 April 2019 14:10 - 15:10