Structural and ⁵⁷Fe Mössbauer study of EuCr _1-xFe _xO ₃ nanocrystalline particles

A structural and Mössbauer study of mechanosynthesized EuCr _1-xFe _xO ₃ nanocrystalline particles (~20-30 nm) is presented. The lattice parameters increase with increasing x-value leading to an increasingly distorted structure. The crystallite sizes range between 20 nm and 30 nm. Magnetic and ⁵⁷Fe Mössbauer measurements show the samples with x < 0. 7 to be paramagnetic and those with x ≥ 0. 7 to be partially superparamagnetic at 298 K. The 78 K Mössbauer spectra of the samples with x = 0. 3-1. 0 are composed of well-resolved two sextets that are explicable in terms of the structural model that we recently have proposed for the EuCrO ₃ nanoparticles according to which the transition metal ions and Eu ³⁺ partly exchange their usual sites in the perovskite-related structure (Widatallah et al. J Phys D Appl Phys 44:265403, 2011). Consequently, the two sextets obtained at 78 K refer to Fe ³⁺ ions at the usual B-octahedral site and the A-dodecahedral site usually occupied by Eu ³⁺.