The results of study of specific heat temperature dependence for the c
rystals [(CH3NH3)(5)Bi2Cl11](1-x) - [(CH3NH3)(5)Bi2Br11](x) (MAPCB - M
APBB) is presented for x = 0, 0.1, 0.43 and 1.0 at the temperature ran
ge 80 - 340 K. Peculiar concentration dependence of the Curie point wa
s revealed supporting the earlier data on dielectric properties. The e
volution of overcritical anomaly of the specific heat for concentratio
n change and under gamma-irradiation is shown.