EFFECT OF TENSILE-STRESS ON THE PHASE-TRANSITION IN CU(2,5-DIMETHYL-N,N'-DICYANOQUINONEDIIMINE)(2) - CORRELATION OF CRYSTAL LENGTH AND CONDUCTIVITY

Citation
H. Hild et al., EFFECT OF TENSILE-STRESS ON THE PHASE-TRANSITION IN CU(2,5-DIMETHYL-N,N'-DICYANOQUINONEDIIMINE)(2) - CORRELATION OF CRYSTAL LENGTH AND CONDUCTIVITY, Solid state communications, 101(8), 1997, pp. 563-567
Citations number
15
Categorie Soggetti
Physics, Condensed Matter
Journal title
ISSN journal
00381098
Volume
101
Issue
8
Year of publication
1997
Pages
563 - 567
Database
ISI
SICI code
0038-1098(1997)101:8<563:EOTOTP>2.0.ZU;2-D
Abstract
Using a new interferometric mechanical set up, we have measured the el ongation and the resistance of deuterated Cu(2,5-dimethyldicyanoquinon ediimine)(2) crystals along the c-direction as functions of temperatur e. The crystal length l decreases with dl/(l . dT) = 1.1 . 10(-4)/K at about 300 K to exhibit a minimum at 50 K. Below 50 K, I increases at further cooling. At the metal-insulator transition detected by a sharp increase of the resistance R(T) at about 70 K, l(T) reveals a smooth step exhibiting a hysteresis between the heating and the cooling cycle as is also observed in R(T). The new setup allowed us to apply tensil e stress which shifts the phase transition to lower temperatures. A mo del for the shrinking of the lattice dimension upon localization of th e charge carriers (disproportion of the mixed valence Cu states) is gi ven, based on static coulombic repulsion only. Young's modulus was det ermined for several temperatures. (C)1997 Elsevier Science Ltd.