Abstract
The cubic to tetragonal phase transition in the solid solutionK(Mn,Ca)F3 has been investigated by conduction calorimetry and x-ray diffraction. Thebehaviour of the excess specific heat, latent heat and spontaneous strainhas been explained in terms of a 2–4–6 Landau potential. The coefficientsA andC, prefactorsof Q2 and Q6 in the free energy expansion, are practically constant with composition, butB (theprefactor of Q4) and TC are functions of composition. The tricritical point occurs when the sign ofB changes fromnegative (in pure KMnF3) to positive (in Ca rich samples). However, the variation of the parametersB andTC with dopant concentrationx is non-linear. Thedependence of TC with composition is explained in terms of an internal stress due to the dopingion of Ca and is compared with the effect of external uniaxial stress on pureKMnF3.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
