Magnetically measured irreversibility temperatures in superconducting oxides and alloys
M Suenaga; D O Welch; R Budhani; M Suenaga; Brookhaven Nat. Lab., Upton, NY, USA; D O Welch; Brookhaven Nat. Lab., Upton, NY, USA; R Budhani; Brookhaven Nat. Lab., Upton, NY, USA
Журнал:
Superconductor Science and Technology
Дата:
1992-01-01
Аннотация:
Irreversibility temperatures T<sub>r</sub>(H) were magnetically measured for the aligned powders of superconducting oxides, La<sub>1.85</sub>Sr<sub>0.15</sub>CuO<sub>4</sub>, YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub>, Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8</sub>, and Bi<sub>2</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10</sub> and for the metallic superconductors Nb, Nb-Ti, Nb<sub>3</sub>Sn and PbMo<sub>6</sub>S<sub>8</sub>. The results are briefly discussed in terms of the thermally activated flux creep and the lattice or the glass melting models for the irreversibility temperatures. Also, the measurement procedures for T<sub>r</sub>(H) using a SQUID magnetometer are described in detail, since the measuring methods and the criteria which are used for T<sub>r</sub>(H) are important in the determination and interpretation of the temperatures.
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