Perpendicular magnetic recording medium and magnetic recording device

摘要

A perpendicular magnetic recording medium and a magnetic recording device with the medium are disclosed. Ferromagnetic crystal grains in a granular magnetic recording layer are grown with a constant grain diameter in a columnar shape, and the nonmagnetic grain boundaries comprise at least two types of oxides or nitrides, preferably of elements selected from Cr, Si, Al, Ti, Ta, Hf, Zr, Y, Ce, and B. The maximum G₁ of absolute values of standard Gibbs free energy of formation for oxidation of ferromagnetic elements composing the ferromagnetic crystal grains, the minimum G₂ and the second smallest G₃ of absolute values of standard Gibbs free energy of formation per 1 mol of oxygen molecules for oxidation of elements composing the nonmagnetic grain boundaries satisfy inequalities G₁23 and (G₂-G₁)>(G₃-G₂) and G₃-G₂ is preferably smaller than 200 kJ/mol. The oxides can be replaced by nitrides, in which case the maximum G₁₁ of absolute values of standard Gibbs free energy of formation per one mole of nitrogen molecules in nitridation of ferromagnetic elements composing the ferromagnetic crystal grain, and the minimum G₁₂ and the second smallest G₁₃ of absolute values of standard Gibbs free energy of formation per one mole of nitrogen molecules in nitridation of elements composing the nonmagnetic grain boundary satisfy the following inequalities G₁₁1213 and (G₁₂-G₁₁)>(G₁₃-G₁₂), and G₁₃-G₁₂ is preferably smaller than 200 kJ/mol.