Crystal structure, magnetic and Mössbauer studies of DyFe Mn1-O3 multiferroic manganites

The influence of iron replacement on the structural and magnetic properties of Dysprosium manganites was studied using the series of DyFe_xMn_1-xO₃ (x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) compounds. All samples were fabricated by means of the modified auto-combustion sol-gel method, followed by the ball milling technique. Orthorhombic structure (Pnma space group) with high phase purity and crystallinity featured all samples, according to X-ray diffraction analysis. The temperature dependence of magnetization curves indicated antiferromagnetic (AFM) to paramagnetic (PM) transition with the increase in temperature. The Néel temperature (T_N) was observed to shift to higher temperatures, whereas the spin reorientation transition temperature (T_SR) reduced as Fe³⁺ content increased. Cusps in the zero-field-cooled (ZFC) curves were detected at low temperatures (around 4 K) as an indication of the ordering of the Dy spin. ⁵⁷Fe Mӧssbauer spectra in samples with low iron content were dominated by a high spin (Fe³⁺) paramagnetic doublet at both 295 K and 78 K, while the distribution in the hyperfine magnetic field accounted for the appearance of the broadening magnetic peaks. High iron samples revealed a magnetic sextet with fit-resolved patterns that indicated a strong AFM coupling of Fe³⁺ ions. The hyperfine magnetic field (B_hf) magnitude demonstrated a linear increase with the increase in iron doping.