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Author(s) |
Sharma, N.; Das, A.; Mishra, S. K.; Prajapat, C. L.; Singh, M. R.; Meena, S. S. (SSPD;TPD)
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Source |
Journal of Applied Physics, 2014. Vol. 115 (21): pp. 213911.1-213911.9 |
ABSTRACT
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The role of doping Fe on the structural, magnetic, and dielectric properties of frustrated antiferromagnet YMn1-xFexO3
(x≤ 0.5) has been investigated. The neutron diffraction analysis shows
that the structure of these polycrystalline samples changes from
hexagonal phase (space group P63cm) to orthorhombic phase (space group Pnma)
for x>0.2. The frustration parameter decreases with Fe substitution.
All the compounds are antiferromagnetic, and the magnetic structure is
described as a mixture of Γ3 and Γ4 irreducible representation (IR) in
the hexagonal phase, and the ratio of these two IRs is found to vary
with Fe doping (x≤0.2). A continuous spin reorientation as a function of
temperature is observed in these samples. The magnetic ground state in
the orthorhombic phase of the higher doped samples (x≥0.3) is explained
by taking Γ1 (GxCyAz) representation of Pnma setting. In YMnO3 suppression of dielectric constant ε′ is observed below TN indicative
of magnetoelectric coupling. This anomalous behavior reduces in Fe
doped samples. The dielectric constant is found to be correlated with
the magnetic moment (M) obtained from neutron diffraction experiments
and follows a M2 behavior close to TN in agreement with Landau theory.
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