Spin dynamics in triangular lattice antiferromagnets CuCr${}_{1-x}$Mg${}_x$O${}_2$

Abstract

The electron spin resonance (ESR) spectroscopy was employed to investigate the spin dynamics in triangular lattice antiferromagnets CuCr${}_{1-x}$Mg${}_x$O${}_2$ with $x=$ 0 and 0.02. All spectra can be well fitted by a single Lorentzian lineshape. The analysis of the $g$ factor, the linewidth $△H$, and the ESR intensity $I$ as a function of temperature suggests the development of significant antiferromagnetic (AFM) spin fluctuations at temperature well above $T_N$ in both samples. However, the evolution of the AFM spin fluctuations is different for each sample. For undoped sample the ESR intensity $I$ is almost temperature independent between $\sim$ 100 K and 50 K and then drops rapidly below 50 K. But for $x=$ 0.02, the $I$ monotonously increases with cooling and reduces rapidly only below $T_N$. These results indicate that the AFM spin fluctuations are extremely strong in the undoped sample and appear to be suppressed upon Mg doping.

5 pages, 4 figures. To be published in Europhysics Letters

References in corpus (4)

• Spin-driven ferroelectricity and possible antiferroelectricity in triangular lattice antiferromagnets ACrO2 (A = Cu, Ag, Li, or Na)
• Direct transition from a disordered to a multiferroic phase on a triangular lattice
• Cascade of magnetic-field-induced quantum phase transitions in a spin $1/2$ triangular-lattice antiferromagnet
• On the strong impact of doping in the triangular antiferromagnet CuCrO2

Cited by in corpus (3)

• Enhanced weak ferromagnetism and conductivity in hole-doped pyrochlore iridate Y2Ir2O7
• Mg substitution in CuCrO2 delafossite compounds
• Influence of Mg, Ag and Al substitutions on the magnetic excitations in the triangular-lattice antiferromagnet CuCrO2