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Studies of the superconducting behavior of polycrystalline YBa[sub 2]Cu[sub 3]O[sub 7-[delta]]

Thesis/Dissertation ·
OSTI ID:7233501
The results of electrical transport and AC susceptibility measurements performed with the goal of studying the superconducting and normal state electrical properties of polycrystalline samples of YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] and Ag/YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] are reported. I-V characteristics and AC susceptibility for [approximately]2 mm diameter sintered polycrystalline YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] pellets are studied at selected magnetic fields 0.1 [le] H [le] 80.9 G and for 80 [le] T [le] 92 K. Temperature dependent changes in I-V isotherms near the superconducting transition are consistent with predictions of critical scaling associated with a superconducting phase transition. AC susceptibility measurements reveal a variety of interesting phenomena, and in particular provide evidence that these materials are gauge glass granular superconductors. Magnetic field and temperature dependent changes in the I-V characteristics of [approximately]15 [mu]m diameter Ag/YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] fibers are studied for 4 [le] T [le] 86 K, for 0.5 [le] H [le] 9000 G, and for 1 [le] J [le] 10[sup 4] A/cm[sup 2]. These measurements reveal a variety of quite different regions of superconducting behavior that are all consistent with a system of weakly coupled superconducting grains.
Research Organization:
Massachusetts Univ., Amherst, MA (United States)
OSTI ID:
7233501
Country of Publication:
United States
Language:
English