SUSCEPTIBILITIES OF SR(CU1-XZNX)(2)O-3 STUDIED BY QUANTUM MONTE-CARLOSIMULATION

The effects of non-magnetic impurities randomly doped into a two-leg H eisenberg spin ladder are investigated, Using the continuous time quan tum Monte Carlo loop algorithm Re calculate the uniform and staggered susceptibilities of such a system. The obtained uniform susceptibility is well described in terms of an effective model of weakly interactin g local moments induced by non-magnetic impurities for a 1% doping cas e, but not for higher concentrations. The staggered susceptibility how ever is significantly enhanced over that in the effective model alread y at 1% doping. Using a mean field approximation for the interladder c oupling, we explain qualitatively the phase diagram of Sr(Cu1-xZnx)(2) O-3.