| Summary: | 碩士 === 國立中正大學 === 物理學系 === 85 === ABSTRACT We report the time-dependent diamagnetic magnetization
for a polycrystalline LuNi2B2C superconductor measured in
magnetic fields 5 kOe, 6 kOe and 7 kOe between 2 K and 13 K with
a Quantum design SQUID magnetometer . The thermally activation
flux-creep model derived by Beasley et al, was employed to
analyze our experimental data. Arrehnius plots of E / kT＝｜M0｜
/ (dM / dlnt) vs 1 / T showed that the apparent activation
energy for LuNi2B2C is strongly dependent on the temperature and
applied magnetic field. From our experimental data, the range of
the apparent activation energy for this material is between 0.7
eV(H＝5 kOe, T ＝7 K∼13 k) and 0.03 eV (H＝7 kOe, T ＝2 K∼4.5
k) .
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