J. Nimmo, B. Lucas
May 22, 1972
Citations
0
Influential Citations
5
Citations
Journal
Nature
Abstract
AT atmospheric pressure, when heated through the transition temperature of ∼ 128° C, potassium nitrate (KNO3) undergoes a phase transformation from an orthorhombic crystal structure (α-phase) to a rhombohedral crystal structure (β-phase)1–4. On cooling from the β-phase, the material passes through an intermediate γ-phase region (∼ 124° C to ∼ 110° C before reverting to the α-phase5–7. The γ-phase is known to exhibit ferroelectric properties8–12. The conformation and orientation of the NO3-group in the various phases of the substance are uncertain4,13,14. We have carried out single crystal studies using elastically-scattered thermal neutrons on potassium nitrate in the γ-phase at 25° C and at 100° C closer to the α→β transition temperature.