The masses of the strange mesons (K, K and phi) are investigated in the presence of strong magnetic fields. The changes in the masses of these mesons arise from the mixing of the pseudoscalar and vector mesons in the presence of a magnetic field. For the charged mesons, these mass modifications are in addition to the contributions from the lowest Landau energy levels to their masses. The decay widths, phi -> KK</mml:mover> and K -> K pi, in the presence of the magnetic field are studied using a field theoretic model of composite hadrons with constituent quarks/antiquarks. The model uses the free Dirac Hamiltonian in terms of the constituent quark fields as the light quark-antiquark pair creation term and explicit constructions for the meson states in terms of the constituent quarks and antiquarks to study the decay processes. The pseudoscalar-vector (PV) meson mixing leads to a drop (rise) in the mass of the pseudoscalar (longitudinal component of the vector) meson. It is observed that the mass modifications for the hidden strange mesons, arising from phi - eta ' mixing, are quite prominent, whereas the neutral open strange mesons have only marginal changes in their masses due to mixing. The mass modifications of the charged open strange mesons are due to interplay between the Landau-level contributions and the PV mixing, and, the latter effect is observed to dominate at large values of the magnetic field. The vector meson decay widths (phi -> KK</mml:mover> and K<mml:mo stretchy="false" class="MathClass-bin"><mml:mo class="MathClass-rel">-> K pi) involving the charged mesons are observed to be quite different from the widths involving neutral mesons, due to the additional contribution for the charged mesons from the Landau levels.
