Effects of grain boundaries on magnetic properties of recording media

Grain boundaries play a crucial role in determining the macroscopic properties of magnetic recording media. The authors employ electronic structure theory, based on the local spin density approximation, to calculate the exchange energy, anisotropy energy, and magnetization at two types of grain boundaries. They incorporate these values into a micromagnetic simulation, thus correlating hysteresis loops and switching properties to atomic features. The authors show that small intergranular spacings (less than 0.2 nm) effectively break exchange, while a larger Cr thickness is required to achieve the same effect.