Peak Effect in Single Crystal [Formula presented] Superconductor for [Formula presented]-Axis

We have studied the phase diagram of the [Formula presented] superconductor using a single crystal for the [Formula presented]-axis. For the first time we report the existence of peak effect in the screening current in the [Formula presented] for the [Formula presented]-axis. In the magnetic field regime [Formula presented] the local fundamental diamagnetic moment displays a very narrow diamagnetic step. For higher fields this step is transformed to a peak (peak effect) and, finally, for [Formula presented] the diamagnetic step is transformed to a gradual transition.