  We have studied the bandwidth-temperature-magnetic field phase diagram of
RE(0.55)Sr(0.45)MnO(3) colossal magnetoresistance manganites with ferromagnetic
metallic (FM) ground state. The bandwidth (or equivalently the double exchange
interaction) was controlled both via chemical substitution and hydrostatic
pressure with a focus on the vicinity of the critical pressure p* where the
character of the zero-field FM transition changes from first to second order.
Below p* the first-order FM transition extends up to a critical magnetic field,
H_cr. It is suppressed by pressure and approaches zero on the larger bandwidth
side where the surface of the first-order FM phase boundary is terminated by a
multicritical end-point (p*~32 kbar, T*~188 K, H*=0). The change in the
character of the transition and the decrease of the CMR effect is attributed to
the reduced CO/OO fluctuations.
