Singlet ground state determined by isolated Cu2+ chain topology in microporous Na2Cu2Si4O11 center dot 2H(2)O and Na2Cu2Si4O11

authors	dos Santos, AM; Amaral, VS; Brandao, P; Paz, FAA; Rocha, J; Ferreira, LP; Godinho, M; Volkova, O; Vasiliev, A
nationality	International
journal	PHYSICAL REVIEW B
keywords	LINEAR-CHAIN; TRANSITION; COMPOUND
abstract	The copper silicate Na(2)Cu(2)Si(4)O(11)center dot 2H(2)O and its dehydrated form Na2Cu2Si4O11 exhibit a singlet ground state at low temperature, which is conditioned by the topology of the isolated edge-sharing CuO6 (or CuO5) chains. The structural analysis of the hydrated and dehydrated forms indicates a strong alternation of the exchange interaction parameter within these chains. The magnetic susceptibility and specific heat measurements confirm spin gaps Delta=96 K for Na(2)Cu(2)Si(4)O(11)center dot 2H(2)O and Delta=85 K for Na2Cu2Si4O11. The reversible dehydration of the water molecules from the microporous framework in the structure affords unique opportunity for tuning the magnetic interaction parameters in these compounds.
publisher	AMERICAN PHYSICAL SOC
issn	1098-0121
year published	2005
volume	72
issue	9
digital object identifier (doi)	10.1103/PhysRevB.72.092403
web of science category	Physics, Condensed Matter
subject category	Physics
unique article identifier	WOS:000232228500010