Magnetic-field and pressure phase diagram of the triangular lattice antiferromagnet CsCuCl${}_3$ clarified by magnetic susceptibility measured with a proximity detector oscillator

Abstract

The effect of pressure ($P$) on magnetic susceptibility of CsCuCl${}_3$ was examined in magnetic fields ($\hat{\mathrm{I}}{¼}_0$$H$) of up to 51 T using a proximity detector oscillator (PDO), and the $H$-$P$ phase diagram of CsCuCl${}_3$ was constructed over the saturation field ($H_{\mathrm{sat}}$). We found that, with increasing $P$, $H_{\mathrm{sat}}$ increases and the uud-phase that appeared at $P$ = 0.7 GPa widened. Based on comparison between the experimental and calculated $H$-$P$ phase diagrams, the Y-phase was predicted to appear above 1.7 GPa. The interchain antiferromagnetic exchange interaction in the $ab$-plane was evaluated and found to increase with increasing $P$, which is consistent with a previous study under high pressure [D. Yamamoto {\it et al.}, Nat. Commun. {\bf 12}, 4263 (2021).]. Moreover, an anomaly was observed below $P$ = 0.6 GPa just below $H_{\mathrm{sat}}$ and might be a new phase transition derived from nonlinear response caused by the PDO technique.

14 pages, 7 figures