Abstract
We performed As-75 NMR studies on two overdoped high-quality Ba1-xKxFe2As2 (x=0.7 and 1.0) single crystals. In the normal states, we found a dramatic increase in the spin-lattice relaxation (1/T-75(1)) from the x =0.7 to the x=1.0 samples. In KFe2As2, the ratio of 1/(T1TKn2)-T-75, where K-75(n) is the Knight shift, increases as temperature drops. These results indicate the existence of another type of spin fluctuations in KFe2As2 which is accustomed to being treated as a simple Fermi liquid. In the superconducting state, the temperature scalings of 1/T-75(1) below T-c in the overdoped samples are significantly different from those in the under or optimally doped ones. A power-law scaling behavior 1/(T1T)-T-75 similar to T-0.5 is observed, which indicates universal strong low-energy excitations in the overdoped hole-type superconductors.
Published in:
Physical Review B 81,1 (2010)
Link to original published article:
http://dx.doi.org/10.1103/PhysRevB.81.012503
Date of Version
January 2010
Recommended Citation
Zhang, S. W.; Ma, L.; Hou, Y. D.; Zhang, J.; Xia, T. L.; Chen, G. F.; Hu, J. P.; Luke, G. M.; and Yu, W., "As-75 NMR study of single crystals of the heavily overdoped pnictide superconductors
Ba1-xKxFe2As2 (x=0.7 and 1)" (2010). Department of Physics and Astronomy Faculty Publications. Paper 1353.
https://docs.lib.purdue.edu/physics_articles/1353