Ferroquadrupolar ordering in a magnetically ordered state in ErNiAl

0557519 - FZÚ 2023 RIV US eng J - Journal Article
Ishii, I. - Kurata, Y. - Wada, Y. - Nohara, M. - Suzuki, T. - Araki, K. - Andreev, Alexander V.
Ferroquadrupolar ordering in a magnetically ordered state in ErNiAl.
Physical Review B. Roč. 105, č. 16 (2022), č. článku 165147. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR(CZ) GA21-09766S; GA MŠMT(CZ) LM2018096
Institutional support: RVO:68378271
Keywords : rare-earth intermetallic compounds * magnetic properties * acoustic properties
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.7, year: 2022
Method of publishing: Limited access
https://doi.org/10.1103/PhysRevB.105.165147

We conducted ultrasonic measurements to clarify whether a phase transition exists in hexagonal compound ErNiAl below the antiferromagnetic transition at 6 K. We discovered a significant elastic softening of the transverse modulus, C66, accompanied by a significant ultrasonic attenuation toward TQ=3.4 K, which is the temperature of a sharp downward peak in other moduli, indicating a phase transition at TQ. The crystal field analysis reveals that the softening of C66 below 80 K is due to an interlevel Oxy-type quadrupole interaction with a positive quadrupole-quadrupole coupling constant between the ground and excited Kramers doublets. A spontaneous expectation value of Oxy emerges at TQ in our crystal field model with the mean-field approximation. No quadrupolar ordering occurs in a magnetically ordered state because the degeneracy of quadrupoles is lifted by an internal magnetic field of magnetic ordering.
Permanent Link: http://hdl.handle.net/11104/0331489