Coexistence of antiferromagnetism and ferromagnetism in
Mn2+/CdS nanocrystals and their photophysical properties
By:Sambandam, B (Sambandam, Balaji)[ 1 ] ; Muthu, SE (Muthu, S. Esaki)[ 2 ] ; Arumugam,
S (Arumugam, S.)[ 2 ] ; Manoharan, PT (Manoharan, Periakaruppan T.)[ 1 ]
RSC ADVANCES
Volume: 3
Issue: 15
Pages: 5184-5195
DOI: 10.1039/c3ra22177f
Published: 2013
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Abstract
Manganous ion doped CdS nanocrystals with different concentrations of Mn2+ have been
synthesized by a chemical synthesis route. The as-synthesized Mn2+/CdS nanocrystals evince
interesting optical emission properties; the intensity of cadmium vacancy emissions V-Cd decreases
on the addition of the dopant ion, proving the displacement of cadmium by manganese which is
accompanied by the appearance and enhancement of the Mn2+ d-d emission, T-4(1)->(6)A(1).
However, the intensity of the latter emission decreases on further increase in [Mn2+] due to strong
cluster formation, such as Mn2+-Mn2+. The low temperature electron paramagnetic resonance
measurements suggest strong antiferromagnetism due to strong exchange coupling between the
spins of nearby Mn2+ centres both in pre- and post-annealed 5% Mn2+/CdS samples. These
magnetic properties for pre- and post-annealed 5% Mn2+/CdS samples are explained by a core/shell
(antiferromagnetism/ferromagnetism) model. The pre-annealed sample, on one hand, shows
antiferromagnetic behavior with weak ferromagnetism below the Neel temperature, the latter due to
uncompensated surface spins. On the other hand, annealing leads to the formation of more Mn2+Mn2+ dimers or clusters due to ionic migration. This will result in increased antiferromagnetic
character as compared to the pre-annealed sample. Both are confirmed by magnetization hysteresis
curves at various temperatures. The electron microscopy images confirm the morphology prediction
by XRD.
Keywords
KeyWords Plus:MAGNETIC-PROPERTIES; PHOTOLUMINESCENCE PROPERTIES; SHAPECONTROL; QUANTUM DOTS; CDS NANORODS;SEMICONDUCTOR NANOCRYSTALS; COO
NANOPARTICLES; DYNAMICS; SURFACTANT; EVOLUTION
Author Information
Reprint Address: Sambandam, B (reprint author)
Indian Inst Technol, Dept Chem, Madras 600036, Tamil Nadu, India.
Addresses:
[ 1 ] Indian Inst Technol, Dept Chem, Madras 600036, Tamil Nadu, India
[ 2 ] Bharathidasan Univ, Ctr High Pressure Res, Sch Phys, Tiruchchirappalli 620024, Tamil Nadu, India
E-mail Addresses:ptm@iitm.ac.in
Funding
Funding Agency
Grant Number
DST
UGC, New Delhi
View funding text
Publisher
ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,
CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Categories / Classification
Research Areas:Chemistry
Web of Science Categories:Chemistry, Multidisciplinary
Document Information
Document Type:Article
Language:English
Accession Number: WOS:000316226500045
ISSN: 2046-2069
Other Information
IDS Number: 107OC
Cited References in Web of Science Core Collection: 46
Times Cited in Web of Science Core Collection: 4