Bridging the gap between micromagnetism and ab initio calculations: basic hysteretic properties of CoPt-type magnets

Abstract We demonstrate how first-principles, microstructural and microscopic model calculations may be combined to obtain material-specific input for micromagnetic calculations. We elucidate the generic links between microstructural features and coercivity of polytwinned CoPt-type magnets. It is shown with the help of ab initio calculations that domain walls in these alloys are strongly attracted to antiphase boundaries, and, using microscopic simulations, that at twin boundaries they are split in magnetostatically coupled segments. We predict a peculiar mechanism of magnetization reversal via DW splitting in ‘partial walls’. General features of magnetization reversal are explained and estimates of coercivity given for the strong and weak pinning cases.