TY - JOUR
T1 - Enhanced room-temperature ferromagnetism on Co-doped CeO2 nanoparticles
T2 - Mechanism and electronic and optical properties
AU - Ranjith, Kugalur Shanmugam
AU - Saravanan, Padmanapan
AU - Chen, Shih Hsien
AU - Dong, Chung Li
AU - Chen, Chih Liang
AU - Chen, Shih Yun
AU - Asokan, Kandasami
AU - Kumar, Ramasamy Thangavelu Rajendra
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2014/11/20
Y1 - 2014/11/20
N2 - The present study reports the effect of Co doping on the structural, optical, magnetic, and electronic properties of CeO2 nanoparticles (NPs) synthesized by a simple low-temperature co-precipitation method. Co doping was introduced by adding CoCl3 with different mole percentages (0%, 2%, 4%, and 6%) to cerium nitrate, which resulted in room-temperature ferromagnetism (RTFM). TEM and XRD analysis showed that the Co-doped CeO2 NPs are monodispersed with face centered cubic structure. The 6% Co-doped CeO2 NPs showed a coercivity value of 155 Oe and saturation magnetization of 0.028 emu/g at room temperature. The electronic structures of the as-prepared CeO2 and Co-doped CeO2 NPs were investigated by X-ray absorption near-edge structure (XANES) spectroscopy. The XANES spectra at Ce M- and L-edges clearly indicated a decrease in the valency state of Ce ions from Ce4+ to Ce3+ upon Co doping. This causes redistribution of oxygen ions and Co-Co bonding. The XANES study revealed that Co doping plays a prominent role in improving the ferromagnetism, as Co replaces the Ce site in the CeO2 cubic lattice and the concentration of oxygen vacancies may not be high enough to form a delocalized impurity band for enhancing the magnetic percolation of Co-doped samples. The XANES spectra at Co L-edges indicate direct Co-Co bond formation in the CeO2 lattices and also a weak bond with O ions. This is in agreement with the magnetic measurements which indicate that Co atoms induce enhancement in magnetic behavior in CeO2 nanostructures. (Graph Presented).
AB - The present study reports the effect of Co doping on the structural, optical, magnetic, and electronic properties of CeO2 nanoparticles (NPs) synthesized by a simple low-temperature co-precipitation method. Co doping was introduced by adding CoCl3 with different mole percentages (0%, 2%, 4%, and 6%) to cerium nitrate, which resulted in room-temperature ferromagnetism (RTFM). TEM and XRD analysis showed that the Co-doped CeO2 NPs are monodispersed with face centered cubic structure. The 6% Co-doped CeO2 NPs showed a coercivity value of 155 Oe and saturation magnetization of 0.028 emu/g at room temperature. The electronic structures of the as-prepared CeO2 and Co-doped CeO2 NPs were investigated by X-ray absorption near-edge structure (XANES) spectroscopy. The XANES spectra at Ce M- and L-edges clearly indicated a decrease in the valency state of Ce ions from Ce4+ to Ce3+ upon Co doping. This causes redistribution of oxygen ions and Co-Co bonding. The XANES study revealed that Co doping plays a prominent role in improving the ferromagnetism, as Co replaces the Ce site in the CeO2 cubic lattice and the concentration of oxygen vacancies may not be high enough to form a delocalized impurity band for enhancing the magnetic percolation of Co-doped samples. The XANES spectra at Co L-edges indicate direct Co-Co bond formation in the CeO2 lattices and also a weak bond with O ions. This is in agreement with the magnetic measurements which indicate that Co atoms induce enhancement in magnetic behavior in CeO2 nanostructures. (Graph Presented).
UR - http://www.scopus.com/inward/record.url?scp=84914673362&partnerID=8YFLogxK
U2 - 10.1021/jp505175t
DO - 10.1021/jp505175t
M3 - Article
AN - SCOPUS:84914673362
SN - 1932-7447
VL - 118
SP - 27039
EP - 27047
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 46
ER -