  The impact of a strong magnetic field, varying with the total baryon number
density, on thermodynamic properties of strange quark matter (SQM) in the core
of a magnetized hybrid star is considered at zero temperature within the
framework of the Massachusetts Institute of Technology (MIT) bag model. It is
clarified that the central magnetic field strength is bound from above by the
value at which the derivative of the longitudinal pressure with respect to the
baryon number density vanishes first somewhere in the quark core under varying
the central field. Above this upper bound, the instability along the magnetic
field is developed in magnetized SQM. The total energy density, longitudinal
and transverse pressures are found as functions of the total baryon number
density.
