  A spin model (for link invariants) is a square matrix $W$ which satisfies
certain axioms. For a spin model $W$, it is known that $W^TW^{-1}$ is a
permutation matrix, and its order is called the index of $W$. F. Jaeger and K.
Nomura found spin models of index 2, by modifying the construction of symmetric
spin models from Hadamard matrices. The aim of this paper is to give a
construction of spin models of an arbitrary even index from any Hadamard
matrix. In particular, we show that our spin models of indices a power of 2 are
new.
