Bv. Kumaraswamy et al., AC-SUSCEPTIBILITY STUDY OF CRITICAL-CURRENT DENSITY IN METAL-SUBSTITUTED ERBA2CU3O7-DELTA, Physical review. B, Condensed matter, 53(10), 1996, pp. 6759-6763
Studies of the ac susceptibility of the pure ErBa2Cu3O7-delta (Er-123)
and the substituted samples ErBa2 (Cu(0.995)M(0.005))(3)O-7-delta (M=
Fe, Ni, Co, Ga) have been made at different ac field amplitudes. Analy
sis of the temperature dependence of the ac susceptibility at these fi
elds [X-T plots] has been done employing Kim's critical state model. T
he dopants are found to lower the temperature-dependent intergranular
critical current density, J(c)(T), of the Er-123 system at different r
ates. Fe doping decreases the J(c) at the highest rate whereas Ni subs
titution results in the least rate of J(c) lowering; the depression ra
tes for Ga and Co doped samples are similar and intermediate. These re
sults fully support the findings of our previous study [Phys. Rev. B 5
2, 1320 (1995)] of the flux creep effects on the same batch of samples
wherein it was observed that the concerned substituents had a similar
effect on the flux creep activation energy values (E(a)) of the syste
m. The lower J(c) of the Fe, Ni, Co, and Ga substituted samples is att
ributed to the reduction in the zero-temperature pinning potential I-0
(O) brought about by the dopants.