title: Thermal Behaviour of Sm0.5 R 0.5FeO3 (R = Pr, Nd) Probed by High-Resolution X-ray Synchrotron Powder Diffraction.
abstract: Mixed ferrites Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 with orthorhombic perovskite structure isotypic with GdFeO3 were synthesized by solid-state reaction technique in air at 1473 K. Structural parameters obtained at room temperature prove a formation of continuous solid solutions in the SmFeO3-PrFeO3 and SmFeO3-NdFeO3 pseudo-binary systems. Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 show strongly anisotropic nonlinear thermal expansion: thermal expansion in the b direction is twice lower than in the a and c directions. The average linear thermal expansion coefficients of Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 in the temperature range of 298-1173 K are in the limits of (9.0-11.1) × 10(-6) K(-1), which is close to the values reported for the parent RFeO3 compounds. Subtle anomalies in the lattice expansion of Sm0.5Pr0.5FeO3 and Sm0.5Nd0.5FeO3 detected at 650-750 K reflect magnetoelastic coupling at the magnetic ordering temperature T N.
authors.affiliation: Lviv Polytechnic National University, 12 Bandera Street, 79013, Lviv, Ukraine. olena_kuz@i.ua.
authors.forename: Olena
authors.initials: O
authors.lastname: Pavlovska
authors.affiliation: Lviv Polytechnic National University, 12 Bandera Street, 79013, Lviv, Ukraine. crystal-lov@polynet.lviv.ua.
authors.forename: Leonid
authors.initials: L
authors.lastname: Vasylechko
authors.affiliation: Lviv Polytechnic National University, 12 Bandera Street, 79013, Lviv, Ukraine. oburyy@yahoo.com.
authors.forename: Oleh
authors.initials: O
authors.lastname: Buryy
keywords: Crystal structure; Magnetoelastic coupling; Mixed rare earth ferrites; Perovskites; Thermal expansion