The Blume-Emery-Griffiths spin glass is studied by renormalization-group
theory in d=3. The boundary between the ferromagnetic and paramagnetic phases
has first-order and two types of second-order segments. This topology includes
an inverted tricritical point, first-order transitions replacing second-order
transitions as temperature is lowered. The phase diagrams show disconnected
spin-glass regions, spin-glass and paramagnetic reentrances, and complete
reentrance, where the spin-glass phase replaces the ferromagnet as temperature
is lowered for all chemical potentials.Comment: Added discussion, references, and figure insets. 5 pages, 6 figures.
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