Magnetic dilution in the cadmium-doped spin ladder compound $Cd_xCu_{1-x}(quinoxaline)Br_2$

Both $Cu(quinoxaline)(Br_2)$ and $Cu(quinoxaline)(Cl_2)$ are examples of molecule-based magnets where the $CuX_4$ dimers are linked into ladders by quinoxaline molecules, where X is either Cl or Br. The rung exchange occurs through the bridging halides while the rail exchange occurs through the quinoxaline rings. Introducing random rung interactions into the system [$Cu (quinoxaline)(Br_2)_{1-x}(Cl_{2})_x$] has caused the spin gap to close, in contrast with the gapped pure spin ladder parents. Crystal growth of non-magnetic-doped molecular magnets, $Cd_xCu_ {1-x}(2,3-dimethylpyrazine)Br_2$, have been performed for several values of the nominal conentration, x, and have been confirmed. The magnetizations and susceptibilities of the magnetically diluted ladder assemblage are presented along with a comparison of the effects of dilution from the pure case (x=0).