Schottky effect in the i -Zn-Ag-Sc-Tm icosahedral quasicrystal and its 1/1 Zn-Sc-Tm approximant

The analysis of low-temperature specific heat of rare-earth (RE)-containing quasicrystals and periodic approximants and consequent interpretation of their electronic properties in the T arrow right 0 limit is frequently hampered by the Schottky effect, where crystalline electric fields lift the dege...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B 2016-02, Vol.93 (5), Article 054208
Main Authors: Jazbec, S., Kashimoto, S., Koželj, P., Vrtnik, S., Jagodič, M., Jagličić, Z., Dolinšek, J.
Format: Article
Language:English
Subjects:
Approximants
Electric fields
Icosahedral phase
Mathematical analysis
Quasicrystals
Rare earth metals
Specific heat
Work functions
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The analysis of low-temperature specific heat of rare-earth (RE)-containing quasicrystals and periodic approximants and consequent interpretation of their electronic properties in the T arrow right 0 limit is frequently hampered by the Schottky effect, where crystalline electric fields lift the degeneracy of the RE-ion Hund's rule ground state and introduce additional contribution to the specific heat. In this paper we study the low-temperature specific heat of a thulium-containing i-Zn-Ag-Sc-Tm icosahedral quasicrystal and its 1/1 Zn-Sc-Tm approximant, both being classified as "Schottky" systems. We have derived the crystal-field Hamiltonian for pentagonal symmetry of the crystalline electric field, pertinent to the class of Tsai-type icosahedral quasicrystals and their approximants, where the RE ions are located on fivefold axes of the icosahedral atomic cluster. Using the leading term of this Hamiltonian, we have calculated analytically the Schottky specific heat in the presence of an external magnetic field and made comparison to the experimental specific heat of the investigated quasicrystal and approximant. When the low-temperature specific heat C is analyzed in a C/T versus T super(2) scale (as it is customarily done for metallic specimens), the Schottky specific heat yields an upturn in the T arrow right 0 limit that cannot be easily distinguished from a similar upturn produced by the electron-electron interactions in exchange-enhanced systems and strongly correlated systems. Our results show that extraction of the electronic properties of RE-containing quasicrystals from their low-temperature specific heat may be uncertain in the presence of the Schottky effect.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.93.054208