Existence of Three Transition Temperatures in Decorated Triangular and Square Ising Lattices with Anisotropic Couplings

It is shown that those decorated triangular and square lattices on which we have investigated the ordering in Ising spins distributed on the lattice sites can have three successive transition temperatures if the exchange couplings are taken different from one direction to another direction of the spin arrays on the lattice. The semi-decorated square lattice which has been found recently by Syozi to have three transition temperatures corresponds to a special one of the square lattice in the present case.