Development of Spin Correlations in Randomly Diluted Quasi-One-Dimensional Spin Systems

Publisher Website
Google Scholar
Abstract
The initial slope of the decreasing Néel temperature T N ( x ), [d( T N ( x )/ T N (0))/d x ] x =0 , in randomly diluted quasi-one-dimensional magnets (TMMC: Cu and (CH 3 ) 3 NHCoCl 3 ·2H 2 O: Mn or Cu) has been investigated down to the infinitesimal impurity concentration x ; x =0.00041 in the case of TMMC: Cu. The development of spin correlation length ξ 1d ( T ) along the magnetic chain has been evaluated from the observed T N ( x ) under zero or finite magnetic fields up to 30 kOe. It has been revealed that even a small amount of impurities which distribute each other with much longer separations than ξ 1d ( T ) give a substantial reduction of the development of ξ 1d ( T ). The rounding of the magnetic heat capacity peak around T N ( x ) is discussed in terms of a new idea of “border concentration” which is characterized by the relation between the length of ξ 1d ( T ) and the inter-impurity distance.