Structural and magnetic properties and evidence of spin-glass behavior induced by Fe-doping in perovskite manganites B-site

AMn 1 − x Fe x O 3 ( A = La 0.75 Ca 0.08 Sr 0.17 and x = 0–0.23 ) compounds, sintered at 700 °C , were characterized by X-ray diffraction (XRD) at room temperature. Rietveld refinement has shown that samples can be indexed in the orthorhombic ( Pnma) structure for low Fe-content ( x ≤ 0.046 ) and rhombohedral ( R - 3 c ) structure for high Fe-content ( x ≥ 0.115 ). The transmission Mössbauer spectra have revealed the same isomer shift δ value assigned to Fe 3+ ion for all compounds. The magnetization behavior and the Curie temperature T C have shown a large dependence on the fractional composition x. In fact, the M(T) curves have revealed the presence of a long-range ferromagnetic state below T C for compounds with x ≤ 0.115, and a spin-glass state (SGS) at low temperature for high Fe-content ( x ≥ 0.177). [Display omitted] ► La 0.75Ca 0.08Sr 0.17Mn 1−xFe xO 3 compounds undergo a transition ortho-rhombo at x=0.046. ► On the rhombohedral phase, the magnetization is governed by the DE interaction ► The magnetization undergoes a strong decrease at high x-values (x≥0.115). ► Compounds show a strong AFM interaction with a spin-glass state at high Fe-content ► Hysteresis loops, M(H) confirm this behavior.