The mechanical behavior of a system near a cooperative ordermdash;disorder transition point is discussed in terms of an Ising model for a set of spins located on mass particles which form a compressible lattice. With the assumption of weak coupling between the lattice and spin systems, it is shown that this Ising model is unstable in the immediate vicinity of its critical point and undergoes a firsthyphen;order transition. In addition, many properties should show hysteresis in the critical region. These general conclusions are illustrated by several twohyphen;dimensional examples.
展开▼
