TY - JOUR
T1 - NQR investigation of high Tc superconductors under pressure
AU - Zheng, Guo qing
AU - Yanase, Etsuya
AU - Ishida, Kenji
AU - Kitaoka, Yoshio
AU - Asayama, Kunisuke
AU - Kodama, Yasuharu
AU - Tanaka, Ritsu
AU - Nakamichi, Sei
AU - Endo, Shoichi
N1 - Funding Information:
Acknowledgment---The authors wlsh to express their thanks to Prof. K. Vosida and Dr. K. Han-zawa for their valuable discussions. This work was partially supported by a Grand-ln-Aid for Science Research on Priority Area, Mechanism of Superconductivity frog the Ninistry of Education, Science and Culture of Japan.
PY - 1991/7
Y1 - 1991/7
N2 - The pressure dependence of the 63Cu nuclear quadrupole resonance (NQR) frequency, νQ, and Tc have been measured for La1.85Sr0.15CuO4 and YBa2Cu4O8 under high pressure up to 1.3GPa. νQ was found to decrease with increasing pressure in La1.85Sr0.15CuO4, while νQ in the CuO2 plane increases with pressure in YBa2Cu4O8. It is evidenced that charge transfer takes place under pressure. Based on the analysis that νQ arises mainly from the on-site holes, a schematic model relating Tc and the ratio of the in-plane hole concentration in the Cu3d and O2p orbitals, n(Cu)/n(O), is constructed. It is proposed that n(Cu)/n(O) is a primarily important factor governing Tc and that the enhancement of Tc under pressure is due to the change of the ratio approaching the most favorable value (∼1).
AB - The pressure dependence of the 63Cu nuclear quadrupole resonance (NQR) frequency, νQ, and Tc have been measured for La1.85Sr0.15CuO4 and YBa2Cu4O8 under high pressure up to 1.3GPa. νQ was found to decrease with increasing pressure in La1.85Sr0.15CuO4, while νQ in the CuO2 plane increases with pressure in YBa2Cu4O8. It is evidenced that charge transfer takes place under pressure. Based on the analysis that νQ arises mainly from the on-site holes, a schematic model relating Tc and the ratio of the in-plane hole concentration in the Cu3d and O2p orbitals, n(Cu)/n(O), is constructed. It is proposed that n(Cu)/n(O) is a primarily important factor governing Tc and that the enhancement of Tc under pressure is due to the change of the ratio approaching the most favorable value (∼1).
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U2 - 10.1016/0038-1098(91)90478-E
DO - 10.1016/0038-1098(91)90478-E
M3 - Article
AN - SCOPUS:0026189917
VL - 79
SP - 51
EP - 55
JO - Solid State Communications
JF - Solid State Communications
SN - 0038-1098
IS - 1
ER -