  A general expression for temperature-dependent magnetic susceptibility of
quantum gases composed of particles possessing both charge and spin degrees of
freedom has been obtained within the framework of the generalized random-phase
approximation. The conditions for the existence of dia-, para-, and
ferro-magnetism have been analyzed in terms of a parameter involving
single-particle charge and spin. The zero-temperature limit retrieves the
expressions for the Landau and the Pauli susceptibilities for an electron gas.
It is found for a Bose gas that on decreasing the temperature, it passes either
through a diamagnetic incomplete Meissner-effect regime or through a
paramagnetic-ferromagnetic large magnetization fluctuation regime before going
to the Meissner phase at BEC critical temperature.
