Cu Nuclear Quadrupole Resonance Study of La2-xSrxCu1-yZnyO4 (x=0.10, 0.15 and 0.20): Zn-induced Wipeout Effect near the Magnetic and Electric Instability

We studied Zn-substitution effect on the high- T c superconductors, underdoped La 2- x Sr x Cu 1- y Zn y O 4 ( x =0.10; y =0, 0.01, 0.02), optimally doped ( x =0.15; y =0, 0.02), and overdoped ( x =0.20; y =0, 0.03, 0.06) in a temperature range of T =4.2–300 K, using Cu nuclear quadrupole resonance (NQR) spin–echo technique. We found full disappearance of the Cu NQR signals for the Zn-substituted, Sr-underdoped x =0.10 samples below about 40 K, partial disappearance for the Sr-optimally doped ones below about 50 K, but not for the overdoped x =0.20 ones. From the Zn-doping, the Sr-doping and the temperature dependence of the wipeout effect, we associate the wipeout effect with Zn-induced Curie magnetism or its extended glassy charge–spin stripe formation.