Published in:

Physical Review B 81,1 (2010)

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.

Date of this Version

January 2010

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.