We study the magnetization dynamics in La-doped yttrium iron garnet thin film induced by a slot line waveguide with the magnetic field applied perpendicular to the plane. The magnetization dynamics depend significantly on the slot line waveguide dimensions, particularly the number of excitation conditions increases with the enlargement of linewidth and the gap between the lines. Such an increase is not observed when the magnetic field is applied to the film plane. The excitation is caused by the interaction between the local magnetization dynamics around the line and the spin waves coming from the other side of the line. Forward volume magnetostatic spin waves are emitted when the magnetic field is applied perpendicular to the film. Their magnetic field dependence of the wavelength change is very gradual, allowing the satisfaction of the resonance condition to be much easier than the in-plane magnetized film.