Unconventional spin excitations in the S= 32 triangular antiferromagnet RbAg₂Cr[VO₄]₂

verfasst von

S. Lee, R. Klauer, J. Menten, W. Lee, S. Yoon, H. Luetkens, P. Lemmens, A. Möller, K. Y. Choi

Abstract

We present muon spin relaxation (μSR) measurements of the S=3/2 undistorted triangular lattice established in RbAg₂Cr[VO₄]₂. The zero-(ZF) and longitudinal-field μSR spectra evidence the absence of spin freezing and long-range magnetic ordering down to T=25 mK, supporting the formation of a dynamic ground state. Noticeably, we observe an anomalous temperature dependence of the ZF muon spin relaxation rate λZF(T), featuring a decrease below T=20 K. This suggests the alteration of the dominant relaxation mechanism by the development of short-range magnetic correlations. A subsequent leveling off of λZF(T) below T=2 K indicates persistent spin dynamics and reveals the presence of exotic magnetic excitations. The field dependence of the muon spin relaxation rate at T=25 mK is well described by a diffusive spin transport model with algebraic spin-spin correlations. The suppressed long-range order and the peculiar temperature-dependent behavior of λZF(T) will be discussed in terms of the exchange interaction between Cr³⁺ moments via nonmagnetic [VO₄]^3- entities. In the title compound, the degeneracy of the t2g-orbital set is not lifted by a space group symmetry reduction or subject to significant anisotropy resulting from spin-orbit coupling.

Externe Organisation(en)

Chung-Ang University
Rutherford Appleton Laboratory (RAL)
Johannes Gutenberg-Universität Mainz
Paul Scherrer Institut (PSI)
Technische Universität Braunschweig

Typ

Artikel

Journal

Physical Review B

Band

101

ISSN

2469-9950

Publikationsdatum

01.06.2020

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Physik der kondensierten Materie

Elektronische Version(en)

https://doi.org/10.1103/PhysRevB.101.224420 (Zugang: Unbekannt)