  We report the experimental observation of a magnetic-field-tuned
superconductor-insulator transition (SIT) in ultrathin TiN films. The low
temperature transport properties of these films show scaling behavior
consistent with a transition driven by quantum phase fluctuations in
two-dimensional superconductor. The magnetoresistance reveals peak and a
subsequent decrease in fields higher than the critical field. The temperature
dependences of the isomagnetic resistance data on the high-field side of the
SIT have been analyzed and the transition from insulating to metallic phase is
found, with at high fields the zero-temperature asymptotic value of the
resistance being equal to h/e^2.
