Frustration can lead to a disordered ground state with a macroscopic degeneracy. A structural and/or magnetic ice system is one in which this frustration can be described by simple local rules describing the configuration of a tetrahedron - the so-called ice rule. In the case of water-ice this rule entails that the central oxygen atoms has two covalent and two hydrogen bonds, for the case of charge ice a two-to-two ratio of cation types, and for the case of spin-ice (for example) the two-in-two-out rule. Because each tetrahedron must obey such a rule, and each tetrahedron shares each site with a neighbouring tetrahedron, the nature of the disorder is naturally spatially correlated.

In this thesis we study a magnetic charge-ice system whose exchange constants are templated by the correlated disorder of the cations. In particular, we present our experimental and theoretical studies on the effects of correlated disorder on structural and magnetic properties of fluoride pyrochlore systems. Using neutron and X-ray scattering along with bulk measurement techniques we study CsNiCrF6 which is a realisation of charge ice state in terms of cations Cr3+ and Ni2+ on the pyrochlore lattice. The goals of the thesis are two-fold, to find out the effects of correlated disorder on the lattice structure and, to reveal the effects of the underlying correlated disorder on magnetism. The works done in the thesis address the effects of correlated disorder on model theoretical systems close to CsNiCrF6, the lattice structure of CsNiCrF6 and magnetism in CsNiCrF6.