Charge-density-wave order and multiple magnetic transitions in divalent Europium compound EuAl4

Koji Kaneko, Takuro Kawasaki, Ai Nakamura, Koji Munakata, Akiko Nakao, Takayasu Hanashima, Ryoji Kiyanagi, Takashi Ohhara, Masato Hedo, Takao Nakama, Yoshichika Ōnuki

研究成果: Article査読

抄録

Multiple transition phenomena in divalent Eu compound EuAl4 with the tetragonal structure were investigated via the single-crystal time-of-flight neutron Laue technique. At 30.0 K below a charge-density-wave (CDW) transition temperature of TCDW = 140 K, superlattice peaks emerge near nuclear Bragg peaks described by an ordering vector qCDW ¼ ð0; 0; δcÞ with δc ∼ 0.19. In contrast, magnetic peaks appear at q2 ¼ ðδ2; δ2; 0Þ with δ2 = 0.085 in a magnetic-ordered phase at 13.5 K below TN1 = 15.4 K. By further cooling to below TN3 = 12.2 K, the magnetic ordering vector changes into q1 ¼ ðδ1; 0; 0Þ with δ1 = 0.17 at 11.5 K and slightly shifts to δ1 = 0.194 at 4.3 K. No distinct change in the magnetic Bragg peak was detected at TN2 = 13.2 K and TN4 = 10.0 K. The structural modulation below TCDW with qCDW is characterized by the absence of the superlattice peak in the (0 0 l) axis. As a similar CDW transition was observed in SrAl4, the structural modulation with qCDW could be mainly ascribed to the displacement of Al ions within the tetragonal ab-plane. Complex magnetic transitions are in stark contrast to a simple collinear magnetic structure in isovalent EuGa4. This could stem from different electronic structures with the CDW transition between two compounds.

本文言語English
論文番号064704
ジャーナルjournal of the physical society of japan
90
6
DOI
出版ステータスPublished - 2021 6 15

ASJC Scopus subject areas

  • 物理学および天文学(全般)

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