Ultrasound investigations of some frustrated and low-dimensional magnets

The investigation of the correlations between magnetic and lattice degrees of freedom provides a better understanding of the underlying physics of frustrated and low-dimensional spin systems. Ultrasound experiments are proven to be a powerful tool to probe the spin-lattice interactions and lattice instabilities. Here, we will present some recent outcome of our ultrasound studies performed at high magnetic fields. We report results of our investigations of the frustrated spin system CdCr₂O₄ [1]. This material shows a wide magnetization plateau, from 28 to 58 T, at one half of the full moment of S = 3/2 Cr³⁺. We further present results for the low-dimensional quantum antiferromagnets Cs₂CuCl₄ [2] and NiCl₂-4SC(NH₂)₂ [3]. The spin-strain coupling is discussed in frame of the exchange-striction mechanism.