N color spin models are introduced and examined in the large N limit. The free energy and critical properties at the phase transition are studied. With relevant couplings between colors the transition becomes either first order or Fisher renormalized. With irrelevant couplings there is a crossover to first-order transitions through a nonclassical tricritical point. Connections are established between the N-color model, compressible systems, and systems with random impurities.
Available at: http://works.bepress.com/miron_kaufman/48/