Structural changes in chlorine-substituted SbSI

Abstract

The antimony sulphoiodide (SbSI) is considered a prospective and important ferroelectric material due to its unique properties below Curie temperature Tc. However, the fact that current practical applications require higher working temperatures has prompted new structural improvements that extend the ferroelectric state. In this ternary system, Tc is highly sensitive to any chemical modifications or stress. Therefore, one way to adjust the Tc is through selective substitution of the constituent elements. In this work, SbSI has been fractionally chlorine-substituted at the iodine site and examined using temperature-dependent x-ray diffraction and specific heat capacity methods. Although a considerable increase in Tc has been achieved, a more detailed analysis shows that the Tc increases with x from 0 to 0.2 and starts to decrease when x > 0.2. The maximum Tc increase in the range of x = 0–0.3 is ∼15.3%. The reverse behavior, from increase to decrease, is thoroughly discussed with reference to the previously published data on SbSI1-xClx compounds.