Structural and Magnetic Properties of Nanosized La0.8Ca0.2Mn1-xFexO3 Particles (0 {= x {= 0.2) Prepared by Sol-Gel Method
Abstrakt
The nanosized La0.8Ca0.2Mn1-xFexO3 (0 {= x {= 0.2) particles were synthesized by sol-gel Pechini method and characterized by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). The magnetic properties have been investigated using magnetic measurements and Mossbauer spectroscopy.
The samples exhibit an average crystallite size of 60 nm with narrow distribution and crystallize within the orthorhombic structure (Pnma space group) From the magnetic point of view, a transition from the ferromagnetic (FM) to paramagnetic (PM) phase at T-C depending on the temperature is observed. The presence of manganese in the structure leads to an increase of the Curie temperature as well as to spontaneous magnetization.
Mossbauer spectra show 70 % of Fe3+ paramagnetically coupled but also 30 % Fe3+ in unexpected strong magnetic interaction. For less iron content the paramagnetic state evidences Griffiths phase due to existence of ferromagnetic clusters.