  Structural analysis of a layered manganese tungstate diaminoalkane hybrid
series suggests that this compound forms a spin-5/2 spin-ladder structure. We
use X-ray diffraction, electron microscopy and x-ray absorption spectroscopy
results to infer the structure. DC magnetization of the manganese compound and
a possible copper analogue appear to show that the manganese system behaves
like 1-dimensional antiferromagnetic Heisenberg chains (i.e. $J_{\parallel} \gg
J_{\perp})$ while the copper system is fitted well by a $S = {1/2}$ spin ladder
model, giving the parameters $g = 1.920 \pm 0.008$, $J_{\parallel}/k_B = -0.3
\pm 1.4$K; $J_{\perp}/k_B = 213.6 \pm 1.1$K. The ability to tune adjacent
inorganic layers of the hybrid materials by altering the length of the organic
`spacer' molecules gives enormous promise for the use of these materials,
especially when doped, to provide a greater understanding of spin ladder
systems.
