LOWER CRITICAL MAGNETIC-FIELD OF LITHIUM-CONTAINING BI2SR2CACU2O8-CRYSTALS(DELTA SINGLE)

Lower critical magnetic field strength at 0 K, H-cl (T); T = 0 K, has been evaluated on single-crystal Bi2.2Sr1.8Ca(Cu1-x, Li-x)(2)O-y with 0 less than or equal to x less than or equal to 0.13 from d.c. suscept ibility data. Significant change is noted between lithium-doped and un doped crystals: the value of H-cl (0) decreases with increasing lithiu m content when the magnetic field is applied to the direction parallel to the ab-plane, i.e. the cleaved crystalline plane, while the value remains constant when the direction of the field is perpendicular to t he ab-plane. This could be attributed to the change in penetration dep th along the c-axis, i.e. lambda(c), with lithium incorporation. Analy ses of diamagnetism versus temperature data were made, which exhibited no significant change in electron-transport mechanism with the variat ion of lithium content.