In this paper a spin-1 spin-glass model under the presence of a uniform
crystal field is investigated. It is shown that the model presents both
continuous and first-order phase transition separated by a tricritical point.
The phase diagram is obtained within the replica-symmetric solution and
exhibits reentrance phenomena at low temperatures. Possibly it is the simplest
model which can describe inverse freezing phenomena.Comment: 12 pages, 1 figur