Single-crystal Cu(II) electron paramagnetic resonance studies on phase transitions in cadmium acetate hexahydrate

Sikdar, Ritobroto; Pal, Arun K.

doi:10.1088/0022-3719/20/30/012

Cited by 5 publications

(7 citation statements)

References 6 publications

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“…The experimental phase transition temperature T c of CaCd 1Ϫx Zn x (CH 3 COO) 4 •6H 2 O single crystals as a function of x is shown in Table I. The values of x in Table I were calculated from the percentage weight ͑w͒ of Zn 2ϩ , using the following relations:…”

Section: Resultsmentioning

confidence: 99%

“…The values of g ʈ of the Cu 2ϩ ion in Zn 2ϩ -doped CCDAH above the phase transition agree fairly well with that for the Cu 2ϩ only doped crystal. 2,4 Whereas the g ʈ value for the Cu 2ϩ crystal increased slightly below T c , it decreases slightly in the case of the Zn 2ϩ -doped crystal with lowering temperature. Though 63 Cu A ʈ increases slightly with lowering temperature in the Zn 2ϩ -doped crystals, the values are almost the same as that for crystals predominantly doped with Cu 2ϩ ions.…”

Section: Discussionmentioning

confidence: 99%

“…11 that for each of the three different types of impurities, the variation of T c in CCDAH crystals with x can be explained fairly well in terms of meanfield theory and a soft vibrational mode of the linear chain Ca-Cd 1Ϫx A x -Ca along the c axis of the crystal. However, this theory, which is also successful in explaining the absence of phase transition in CaCu(CH 3 COO) 4 •6H 2 O, requires different values of T co and 0␦ 2 /K for the three types of impurities ͑see Table I and Ref. 8͒.…”

Section: Discussionmentioning

confidence: 99%

“…The crystal structure of cadmium calcium acetate hexahydrate, CaCd(CH 3 COO) 4 •6H 2 O ͑CCDAH͒, is isomorphous with that of copper calcium acetate hexahydrate, CaCu(CH 3 COO) 4 •6H 2 O ͑CCUAH͒. 1 Both have tetragonal symmetry belonging to the space group I4/m.…”

Section: Introductionmentioning

confidence: 99%

“…6 Using the EPR of Cu 2ϩ as a probe, the phase transition temperature T c of CaCd 1Ϫx Cu x (CH 3 COO) 4 •6H 2 O is found to vary from 144 to 124 K as the atomic concentration of copper varies from 0.07% (xϭ0.005) to 1.32% (xϭ0.1022) of the sample weight, where x is the atomic fraction of Cu 2ϩ . 5 The phase transition temperature of pure CCDAH ͑i.e., xϭ0͒, T co , was deduced from this study to be 145 K. 5 To shed some light on the modification of phase transition temperature of CCDAH by impurities, Oguama, Shields, and De 8 carried out detailed EPR studies of phase transition in CCDAH doped with Mn 2ϩ ions of various atomic concentrations, x.…”

Section: Introductionmentioning

confidence: 99%

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EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
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1
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The effect of Zn 2ϩ ion impurities on the phase transition temperature of single crystals of calcium cadmium acetate hexahydrate ͑CCDAH͒ has been studied using the electron-paramagnetic-resonance technique. The lowering of the phase transition temperature as a function of increasing Zn 2ϩ impurity ion concentration in the crystals has been observed to be quite different from that found in our earlier studies of Cu 2ϩ and Mn 2ϩ ion doped crystals. Though the observed lowering of phase transition temperature with atomic fraction x of the Zn 2ϩ impurity ion can be explained fairly well in terms of mean-field theory and a soft mode arising out of the harmonic vibration of the Ca-Cd (1Ϫx) Zn x -Ca chain along the c axis of the crystal, contrary to expectation, values of constants ͑such as the ratio of the square of the soft-mode frequency before transition, the mean-field constant, and the phase transition temperature, etc. of the pure crystal͒ are quite different from that obtained by fitting the phase transition temperatures in the Cu 2ϩ ion only impurity doped crystals. The temperature variation of the spin-Hamiltonian parameters of the Cu 2ϩ ion probe in the Zn 2ϩ -doped crystal of CCDAH is somewhat different from that in the Cu 2ϩ ion only doped crystal. Deviation from mean-field theory is then considered in the Zn 2ϩ impurity driven modification of phase transition of the crystal and good agreement between the observed and computed values of phase transition temperature as a function of the Zn 2ϩ atomic fraction has been obtained using the same values of the said constants as obtained for Cu 2ϩ ion only impurity doped crystals.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
0
1
0
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Molecular structural identification of Cu(II) ion in Diaquamalonatozinc(II): Anisotropic behavior with low hyperfine coupling constant

Mithira

Natarajan

Deepa

et al. 2007

Journal of Molecular Structure

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The phase transition temperature at 145 K in cadmium calcium acetate hexahydrate as a function of Cu2+ probe concentration

Shields

Kleman

1992

The Journal of Chemical Physics

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The temperature of the structural phase transition in cadmium calcium acetate hexahydrate as a function of Cu2+ concentration has been studied with electron paramagnetic resonance (EPR). The phase transition temperature was found to vary from 144 to 124 K as the amount of copper varied from 0.07% to 1.3% of the sample weight. An extrapolation of this data predicts a structural phase transition at 145 K in pure cadmium calcium acetate hexahydrate. Good fits of the data to second-order phase transition theory was obtained with critical exponents close to 0.30.

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Single-crystal Cu(II) electron paramagnetic resonance studies on phase transitions in cadmium acetate hexahydrate

Cited by 5 publications

References 6 publications

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
0
1
0
View full text Add to dashboard Cite

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
0
1
0
View full text Add to dashboard Cite

Molecular structural identification of Cu(II) ion in Diaquamalonatozinc(II): Anisotropic behavior with low hyperfine coupling constant

The phase transition temperature at 145 K in cadmium calcium acetate hexahydrate as a function of Cu2+ probe concentration

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Single-crystal Cu(II) electron paramagnetic resonance studies on phase transitions in cadmium acetate hexahydrate

Cited by 5 publications

References 6 publications

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CHDe1 2002Phys. Rev. B16010View full textAdd to dashboardCite

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CHDe1 2002Phys. Rev. B16010View full textAdd to dashboardCite

Molecular structural identification of Cu(II) ion in Diaquamalonatozinc(II): Anisotropic behavior with low hyperfine coupling constant

The phase transition temperature at 145 K in cadmium calcium acetate hexahydrate as a function of Cu2+ probe concentration

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EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
0
1
0
View full text Add to dashboard Cite

EPR studies of the effect ofZn2+ion impurities in phase transition ofCaCd(CH
De
¹

2002
Phys. Rev. B
16
0
1
0
View full text Add to dashboard Cite