Abstract
In this paper, we focus on the Cs-doping effect at the La-site in La1-xCsxMnO3 (x = 0; 0.05 and 0.1) manganite. Synthesized powders via the sol-gel auto-combustion route have been characterized by structural and magnetic measurements. All samples crystallize into a rhombohedral structure with R 3‾ c space group as confirmed by Rietveld analysis of the X-ray diffraction (XRD) patterns. The diffraction analyses as function of temperature reveal a linear evolution of the structural parameters influencing the Jahn-Teller (J-T) distortion. Spherical nanoparticles have been observed by scanning electron microscopy (SEM). The energy-dispersive X-ray spectroscopy (EDS) analyses confirmed the expected presence of La, Cs, Mn and O ratio, as well as the phase purity of the synthesized materials. The polycrystalline grain structure was confirmed by transmission electron microscopy (TEM), where crystallite size obtained from TEM ranges from 21 nm to 120 nm as function of the composition and sintered temperature. The lattices fringes resolved in the high-resolution TEM (HRTEM) images confirmed the crystal rhombohedral symmetry of our compounds. X-ray photoelectron spectroscopy (XPS) studies demonstrate the mixed valence states of manganese ions (Mn4+ and Mn3+) in undoped as well as doped systems. The electron spin resonance (ESR) analyses confirmed the decreasing of the ferromagnetic ordering versus the increase of Cs doping. Soft ferromagnetism has been observed in all our La1-xCsxMnO3 (x = 0; 0.05 and 0.1) samples which can be attributed to the super exchange interaction between the magnetic ions. Surprisingly enough, the magnetization behavior is found to be a sum of ferromagnetic (FM), superparamagnetic (SPM) and paramagnetic (PM) contributions at low temperature (i.e. 4K). As expected, their behavior is PM at room temperature. This work shows how structural and magnetic properties can be greatly affected by small amount of La-substitution by Cs.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
