Abstract
Spectra of magnetosonic waves are studied by taking account of spin-up and spin-down electrons as two different fluids. It is found that the electron spin effect modifies the dispersions of the perpendicular and obliquely propagating magnetosonic waves even without considering the magnetization current effect. It may be noted that previously the spin effect in these dispersions appeared only due to magnetization. Furthermore, the consideration of separate spin evolution gives rise to the existence of a new spin dependent mode, i.e., spin magnetoacoustic mode along with fast and slow magnetosonic modes. It is also noted that spin polarization reduces the wave frequency of spin magnetoacoustic waves and fast magnetosonic waves while the frequency of the slow mode was slightly affected by these effects. The relevance of the present investigation in the dense astrophysical environments is also pointed out.