Successive phase transitions to antiferromagnetic and weak-ferromagnetic long-range orders in quasi-one-dimensional antiferromagnet Cu${}_3$Mo${}_2$O${}_9$

Abstract

Investigation of the magnetism of Cu${}_3$Mo${}_2$O${}_9$ single crystal, which has antiferromagnetic (AF) linear chains interacting with AF dimers, reveals an AF second-order phase transition at $T_{\mathrm{N}}=7.9$ K. Although weak ferromagnetic-like behavior appears at lower temperatures in low magnetic fields, complete remanent magnetization cannot be detected down to 0.5 K. However, a jump is observed in the magnetization below weak ferromagnetic (WF) phase transition at $T_{\mathrm{c}}\simeq 2.5$ K when a tiny magnetic field along the a axis is reversed, suggesting that the coercive force is very weak. A component of magnetic moment parallel to the chain forms AF long-range order (LRO) below $T_{\mathrm{N}}$, while a perpendicular component is disordered above $T_{\mathrm{c}}$ at zero magnetic field and forms WF-LRO below $T_{\mathrm{c}}$. Moreover, the WF-LRO is also realized with applying magnetic fields even between $T_{\mathrm{c}}$ and $T_{\mathrm{N}}$. These results are explainable by both magnetic frustration among symmetric exchange interactions and competition between symmetric and asymmetric Dzyaloshinskii-Moriya exchange interactions.

7 pages, 7 figures

References in corpus (1)

• Magnetically driven ferroelectric order in Ni${}_3$V${}_2$O${}_8$