Growth and characterization of pure and doped single crystals of CuGeO3

Good quality single crystals of copper metagermanite, CuGeO3, are grown by flux technique. Growth is carried out at relatively low temperatures by usi ng Bi2O3 along with CuO in an optimal flux ratio. Besides rendering the pro cedure simple, lower growth temperature reduces growth defect concentration . Single crystals of Cu1 - xCoxGeO3 and CuGe1 - yGayO3 are grown by the sam e method for different values of x and y to investigate the influence of in -chain and off-chain doping on spin-Peierls (SP) transition. Change in colo r, morphology and surface features as a result of doping are briefly discus sed. Spin-Peierls transition of these crystals is studied by susceptibility measurements on a commercial SQUID magnetometer. Cationic substitution res ulted in reduction of spin-Peierls transition temperature (T-SP) of CuGeO3. Substitution of magnetic impurity cobalt in-chain site caused more pronoun ced effects such as suppression of SP phase. (C) 1999 Elsevier Science B.V. All rights reserved.