Rapid microwave assisted synthesis of Mn2O3 and Co3O4 nanoparticles and their structural, optical and magnetic properties

Abstract

The Mn2O3 and Co3O4 nanoparticles were synthesized by rapid microwave assisted method and as
synthesized samples were further annealed at 550 οC and the samples were subjected to analyze structural, optical and
magnetic properties. Structural properties of the nano particles were characterized by using X-ray diffractometry. XRD
pattern revealed that the existence of Mn2O3 with body centered cubic structure and Co3O4 with face centered cubic
structure. The FTIR spectra confirmed the presence of Mn-O stretching vibration mode at 523 and 575 cm-1
and
absorption bands appeared at 567 and 647 cm-1 were attributed to Co-O stretching and O-Co-O bridging vibration
modes. The Raman bands of Mn2O3 were assigned at 368, 483 and 652 cm-1 which attributed to the out-of-plane bending
modes of Mn2O3, asymmetric stretching of bridge oxygen species of Mn-O-Mn and symmetric stretching of Mn2O3 groups
respectively. Further, major Raman bands of Co3O4 appeared at 670 cm
-1
is attributed to characteristic of the octahedral
site and other three modes are likely related to the combined vibration of tetrahedral site and octahedral oxygen motions
of Co3O4. The PL spectra exhibited strong blue emission band at 489 and 488 nm and weak defect-related green
emission band at 512 and 505 nm for Mn2O3 and Co3O4. The magnetic properties were studied by vibrating sample
magnetometer (VSM) in both samples at an ambient temperature and the M (H) curves of Co3O4 exhibit ferromagnetic
nature and Mn2O3 shows antiferromagnetic behavior. From these results, both materials are more suitable for magnetic
applications.