High-resolution studies of cubic perovskites by elastic neutron diffraction: CsPbCl₃

Abstract

A programme of elastic neutron-diffraction experiments has been undertaken to derive (and compare) atomic distribution functions, with high spatial resolution, for the antiferroelectric perovskites SiTiO3, KMnF3, RbCaF3 and CsPbCl3 in their cubic phase. The study of cubic CsPbCl3 is presented. Data were collected out to a resolution limit of sin theta lambda =1.2AA-1, and used in least-squares refinements of parameters describing anharmonic distributions for the Cs, Pb and Cl ions. Two different techniques yield essentially the same conclusions: anharmonicity is very much more significant for the Cl ion than for the metals and, the inharmonic parameters for Cl correspond to a small bulging of its distribution in the directions along which Cl is known to displace on passing to the low-temperature phase.