Linear magnetoelastic coupling and magnetic phase diagrams of the buckled-kagomé antiferromagnet $$\hbox {Cu}_3\hbox {Bi}{(\hbox {SeO}_3)_2}\hbox {O}_2\hbox {Cl}$$

Abstract

AbstractSingle crystals of Cu$$_3$$ 3 Bi(SeO$$_3$$ 3 )$$_2$$ 2 O$$_2$$ 2 Cl were investigated using high-resolution capacitance dilatometry in magnetic fields up to 15 T. Pronounced magnetoelastic coupling is found upon evolution of long-range antiferromagnetic order at $$T_{\mathrm {N}}$$ T N  $$= 26.4(3)$$ = 26.4 ( 3 )  K. Grüneisen analysis reveals moderate effects of uniaxial pressure on $$T_{\mathrm {N}}$$ T N , of 1.8(4) K/GPa, $$-0.62(15)$$ - 0.62 ( 15 )  K/GPa and 0.33(10) K/GPa for $$p \parallel a$$ p ‖ a , b, and c, respectively. Below 22 K Grüneisen scaling fails which implies the presence of competing interactions. The structural phase transition at $$T_{\mathrm {S}}$$ T S  $$= 120.7(5)$$ = 120.7 ( 5 )  K is much more sensitive to uniaxial pressure than $$T_{\mathrm {N}}$$ T N , with strong effects of up to 27(3) K/GPa ($$p \parallel c$$ p ‖ c ). Magnetostriction and magnetization measurements reveal a linear magnetoelastic coupling for $$B\parallel c$$ B ‖ c below $$T_{\mathrm {N}}$$ T N , as well as a mixed phase behavior above the tricritical point around 0.4 T. An analysis of the critical behavior in zero-field points to three-dimensional (3D) Ising-like magnetic ordering. In addition, the magnetic phase diagrams for fields along the main crystalline axes are reported.