On the low temperature specific heat of Ni(en)/sub 2/Ni(CN)/sub 4/ and Ni(en)/sub 2/Ni(CN)/sub 4//spl middot/2.5H/sub 2/O

摘要

Specific heat measurements on Ni(en)/sub 2/Ni(CN)/sub 4/ (where en=C/sub 2/H/sub 8/N/sub 2/) and Ni(en)/sub 2/Ni(CN)/sub 4//spl middot/2.51H/sub 2/O in the temperature region from 60 mK to 10 K are presented. No indication of a three-dimensional ordering is observed down to 60 mK. Both compounds appear to be good representatives of antiferromagnetic S=1 Heisenberg linear chain systems with D/k=6 K, D/|J|=10 and D/k=6.3 K, D/|J|=50, respectively.