The thermodynamics of random field Ising model (RFIM) on Bethe lattice is
studied by using the replica trick (Bethe lattice is placed in an external
magnetic field (B)). A Gaussian distribution for random field with variance
2
RF
2
i h = H is considered. The free-energy (F), magnetization (M), order
parameter (q), susceptibility ( χ ) and internal energy (U) are calculated. The
phase diagram is investigated at different values of co-ordination number
z = 3,4,5,6 and z → ∞ . The phase diagram shows several interesting
behaviours and present tricritical point at critical
temperatureT J k c = / , = 0 RF H for finite co-ordination number (z). The
critical temperature ( c T ) and the corresponding value of RF H are found.
Finally, we compare our results with the recent results obtained before for spins
glasses.