CLEAR DISTINCTION BETWEEN THE UNDERDOPED AND OVERDOPED REGIME IN THE T-C SUPPRESSION OF CU-SITE-SUBSTITUTED HIGH-T-C CUPRATES

The T-c suppression by Cu-site substitution has been studied in a wide range of carrier concentrations p, from the underdoped regime to the overdoped regime, using sintered polycrystals of Bi2Sr2Ca1-xYx (Cu(1-2 )M(z))(2)O-8+delta with x=0; and x=0.3 and under variation of delta. T he carrier-dependent strength of the T-c suppression by substituting M =Fe, Co, Ni, Zn for Cu is measured. In the overdoped regime, we find T -c scaling as T-c(p,z)/T-c(p,0)=g(z) with a p-independent function g(z ), whereas in the underdoped regime T-c(p,z)/T-c(p,0) is strongly p de pendent. Replotting data of various publications on the La2-xSrxCuO4 s ystem and comparison with the YBa2Cu3O7-delta system demonstrate the u niversality of this distinction between the two regimes in p-type high -T-c cuprates. The scaling behavior is discussed with respect to Born- limit and unitarity-limit scattering.