• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1675-1680
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• 2012

Three new cyanide-bridged $Cr^{III}Mn^{II}$ binuclear complexes, $[Mn(phen)_2Cl][Cr(bpmb)(CN)_2]{\cdot}H_2O$ ($\mathbf{1}$) (phen = 1,10-phenanthroline, $bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate), $[Mn(phen)_2Cl][Cr(bpmb)-(CN)_2]{\cdot}H_2O$ ($\mathbf{2}$) ($bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate), and $[Mn(phen)_2Cl]-[Cr(bpClb)(CN)_2]{\cdot}CH_3OH{\cdot}H_2O$ ($\mathbf{3}$) ($bpClb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate) were obtained based on $Mn(phen)_2Cl_2$ and a series of dicyanidechromate(III) building blocks. Single crystal X-ray diffraction analysis shows the structures of the three complexes are dimeric type with two different metal centers linked by a cyanide group from corresponding dicyanidechromate(III) building block. Magnetic investigations indicate the existence of relatively weak antiferromagnetic coupling between Cr(III) and Mn(II) ions with best-fit constants $J_{CrMn}=-2.78(5)cm^{-1}$ for $\mathbf{1}$, $J_{CrMn}=-3.02(2)cm^{-1}$ for $\mathbf{2}$ and $J_{CrMn}=-2.27(3)cm^{-1}$ for $\mathbf{3}$ based on the spin exchange Hamiltonian = $-2J_{CrMn}\hat{S}_{Cr}\hat{S}_{Mn}$. The magneto-structural correlation of cyanide-bridged $Cr^{III}Mn^{II}$ complexes has been discussed at last.

• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.177-180
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• 2005

Ferroelectric $LiTaO_3$ single crystals, grown by the Czochralski method, were thermally treated at temperature $1000^{\circ}C\;and\;1100^{\circ}C$. Electron paramagnetic resonance (EPR) study of stoichiometric $LiTaO_3$ and thermally treated $LiTaO_3$ crystals has been investigated by employing an X-band spectrometer. From the $Fe^{3+}$ EPR spectra, it turned out that there is no change of site location and local site symmetry around $Fe^{3+}$ impurity ion between stoichiometric and thermally treated $LiTaO_3$ single crystals. We confirmed that the ionic state of $Fe^{3+}$ ion changed after thermal treatment. The EPR parameters of $Fe^{3+}$ ion in $LiTaO_3$ single crystals are determined with effective spin Hamiltonian.

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.118-124
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• 2005

We have obtained sharp and clearly resolved ESR spectra of $Nd^{3+}$ and $Er^{3+}$ in vapor transport equilibrium (VTE) treated $LiNbO_3$ crystals, consequently have determined more accurate spin Hamiltonian parameters, than those in congruent samples. The anisotropic hyperfine structures of $^{143}Nd^{3+}$ and $^{145}Nd^{3+}$ in the VTE-treated crystals at liquid helium temperature have been analyzed. It is proposed that both rare earth ions favor the lithium site in $LiNbO_3$ from the consideration of the determined anisotropic g-values.

• Journal of the Korean Magnetics Society
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• v.21 no.6
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• pp.208-213
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• 2011

We calculated the EPR (electron paramagnetic resonance) line-shape function. The line-widths of a -doped single crystal was studied as a function of the temperature with 0.5 and 2 at. at a frequency of (X-band). The line-width decreases with increasing temperature, such temperature behavior of the line-width can indicate a motional narrowing of the spectrum, when impurity ions substitute for host ions in an off-center position, and thus there can be fast jumping of dipoles between several symmetrically equivalent configurations. Therefore, the present technique is considered to be more convenient to explain the resonant system as in the case of other optical transition problems.

• Journal of the Korean Magnetics Society
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• v.26 no.2
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• pp.45-49
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• 2016

Ground state energy levels of $Gd^{3+}$ ion (effective spin S = 7/2) in $PbWO_4$ single crystal doped with $Gd^{3+}$ paramagnetic impurity at tetragonal symmetry are calculated with spectroscopic splitting parameters and zero field splitting parameters using by effective spin Hamiltonian. It turns out that the zero field splitting energies of $Gd^{3+}$ ion were the same regardless of the directions of $PbWO_4$ : Gd single crystal. The calculated energy differences for ${\mid{\pm}7/2}$ > ${\leftrightarrow}{\mid{\pm}5/2}$ >, ${\mid{\pm}5/2}$ > ${\leftrightarrow}{\mid{\pm}3/2}$ >, and ${\mid{\pm}3/2}$ > ${\leftrightarrow}{\mid{\pm}1/2}$ > transitions were 6.9574 GHz, 6.9219 GHz, and 15.8704 GHz, respectively when the applied magnetic field is zero. The calculated energy level diagrams were different for different directions of applied magnetic field. For B // a- and c-axis, the energy level diagrams are calculated and discussed.

• Journal of the Korean Magnetics Society
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• v.13 no.4
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• pp.171-175
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• 2003

Electron paramagnetic resonance (EPR) of Fe$^{3+}$ in LiTaO$_3$ single crystal, grown by Czochralski method, has been studied by employing an X-band spectrometer. Resonance spectra of Fe$^{3+}$ ion on the crystallographic principal axes were obtained with 9.447 ㎓ at room temperature. The spectroscopic splitting parameter g and zero-field splitting (ZFS) parameter D (= 3 B$_{2}$sup 0/) are calculated with effective spin Hamiltonian. Fe$^{3+}$ center in stoichometric single crystal turns out to be different with that in congruent single crystal reported previously. From the analysis of temperature dependence of resonance fields for Fe$^{3+}$ ion, there is no any phase transition at the temperature range (from -160 $^{\circ}C$ to 20 $^{\circ}C$).