Elastic Softening in the Metallic Antiferromagnet YbCuGe

International Conference on Strongly Correlated Electron Systems 2016

Xi, X.J.^1 ; Ishii, I.^1 ; Noguchi, Y.^1 ; Goto, H.^1 ; Kamikawa, S.^1 ; Araki, K.^2 ; Katoh, K.^2 ; Suzuki, T.^1,3,4

Department of Quantum Matter, ADSM, Hiroshima University, Higashihiroshima, Hiroshima

739-8530, Japan^1

Department of Applied Physics, National Defense Academy, Kanagawa, Yokosuka

239-8686, Japan^2

Institute for Advanced Materials Research, Hiroshima University, Higashihiroshima, Hiroshima

739-8530, Japan^3

Cryogenics and Instrumental Analysis Division, N-BARD, Hiroshima University, Higashihiroshima, Hiroshima

739-8526, Japan^4

关键词: Crystalline electric field effects;    Elastic softening;    Hexagonal structures;    High temperature range;    Longitudinal modulus;    Magnetic frustrations;    Quadrupole interactions;    Transverse elastic moduli;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/807/1/012012/pdf
DOI  :  10.1088/1742-6596/807/1/012012

来源: IOP

【 摘 要 】

The Yb-based compound YbCuGe with a hexagonal structure is reported as a metallic antiferromagnet with TN= 4.2 K. It is also proposed that this compound contains geometrical magnetic frustration due to the competition of exchange interaction within the quasi-two dimensional Yb plane of which Yb ions form a triangle. Previous research suggested that its magnetic anisotropy can be ascribed to the crystalline electric field (CEF) effect on a single Yb ion. In order to clarify the CEF effect in this compound, ultrasonic measurements and related theoretical fitting have been carried out. The transverse elastic modulus C44 exhibits a softening which begins at 120 K and stops at about 20 K. On the other hand, the longitudinal modulus C33mode shows a continuous hardening before TN. We carried out the theoretical strain-susceptibility calculation of C44 by using the CEF parameters reported by Katoh et al. According to the fitting results, it can be concluded that the softening at high temperature range can be explained by the quadrupole interaction between the ground and excited Kramers doublets under the hexagonal CEF.