Amorphous state ferroelectricity, magnon scattering and phase stability in microparticle materials

Abstract

Microparticles and micrograin ceramics show features distinct from the usual-sized polycrystalline materials. Amorphous state material combined with microparticle size for Pb(Zr0.51 Ti0.49)O3 mimics the dielectric behaviour of crystalline ferroelectricity in ABO3 compounds. Fine-grained Y3Fe5O12 (yig) synthesized by pressure sintering of yig microparticles exhibit spinwave relaxation due to transit time across grain diameter. Applying microemulsion techniques for microparticle synthesis, γ-Fe2O3 has been synthesized. The phase stability fraction γ-Fe2O3/α-Fe2O3 is found to be a function of particle size. At very small sizes γ-Fe2O3 becomes amorphous, leading to interesting Mössbauer studies. © 1984 The Indian Academy of Sciences.