${\mathrm{Sm}}_2{\mathrm{Ti}}_2{\mathrm{O}}_7$, a member of the rare-earth titanate pyrochlores, exhibits dipolar-octupolar antiferromagnetism below $T_N=0.35\mathrm{K}$. We observed two ferroelectric transitions at 182 ($T_{\text{FE}1}$) and 52 K ($T_{\text{FE}2}$), significantly higher than $T_N$ for ${\mathrm{Sm}}_2{\mathrm{Ti}}_{2-x}{\mathrm{V}}_x{\mathrm{O}}_7$ ($x=0,0.1$). Although the ferroelectric transition temperatures remain unchanged, the polarization value decreases with V doping. A structural transition to a polar $R3m$ rhombohedral phase from the cubic $Fd\overline{3}m$ structure occurs at $T_{\text{FE}1}$ for the pristine compound, involving a distortion in the pyrochlore lattices formed by the Sm atoms. Remarkably, linear magnetoelectric coupling is observed in both compounds, with further enhancement of magnetoelectric (ME) coupling due to magnetic V doping. The existence of magnetoelectric coupling without long-range magnetic order is of fundamental interest for advancing the understanding and development of ME coupling.

Close

PrevNext

View figure in article

• Frustrated magnetism
• Magnetoelectric effect
• Structural phase transition
• Multiferroics