Crystal growth and magnetic behaviour of pure and doped SrCu2(11BO3)2

High quality single crystals of incongruently melting SrCu2(BO3)2, both pure and doped with Mg, La and Na have been grown by optical floating zone (OFZ)-image furnace technique using self-flux. The obtained single crystals were characterized by X-ray powder diffraction and by neutron scattering using highly enriched 11B for selected crystals. Magnetic susceptibility measurements from 3 to 300 K, with a magnetic field parallel to the ab plane were performed on pure and doped crystals oriented by the Laue method. The measurements show a relatively complex behaviour and confirm the formation of a spin singlet ground state at low temperatures. No evidence of superconductivity is observed.