EPR studies of the effect of Zn2+ ion impurities in phase transition of CaCd(CH3C00) 4·6H20 crystals
| dc.creator | De, Dilip Kumar | |
| dc.date | 2002 | |
| dc.date.accessioned | 2025-03-27T18:59:17Z | |
| dc.description | The effect of Zn2+ ion impurities on the phase transition temperature of single crystals of calcium cadmium acetate hexahydrate (CCDAH) has been studied using the electron-paramagnetic-resonance technique. The lowering of the phase transition temperature as a function of increasing zn2+ impurity ion concentration in the crystals has been observed to be quite different from that found in our earlier studies of Cu2 + and Mn2 + ion doped crystals. Though the observed lowering of phase transition temperature with atomic fraction x of the Zn2+ 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(l-x)Znx-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 crystal) are quite different from that obtained by fitting the phase transition temperatures in the Cu2+ ion only impurity doped crystals. The temperature variation of the spin-Hamiltonian parameters of the Cu2+ ion probe in the Zn2+ -doped crystal of CCDAH is somewhat different from that in the Cu2+ ion only doped crystal. Deviation from mean-field theory is then considered in the Zn2+ 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 Zn2+ atomic fraction has been obtained using the same values of the said constants as obtained for Cu2+ ion only impurity doped crystals. | |
| dc.format | application/pdf | |
| dc.identifier | http://eprints.covenantuniversity.edu.ng/5118/ | |
| dc.identifier.uri | https://repository.covenantuniversity.edu.ng/handle/123456789/34417 | |
| dc.language | en | |
| dc.subject | QH301 Biology | |
| dc.title | EPR studies of the effect of Zn2+ ion impurities in phase transition of CaCd(CH3C00) 4·6H20 crystals | |
| dc.type | Article |
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