Berlin 2012 – wissenschaftliches Programm

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SYTM: Symposium Tailoring magnetism in L1₀-ordered nanostructures: Perspectives for magnetic recording beyond 1 Terabit/in²

SYTM 1: Tailoring magnetism in L1₀ ordered nanostructures: Perspectives for magnetic recording beyond 1 Tb/in²

SYTM 1.4: Hauptvortrag

Montag, 26. März 2012, 11:00–11:30, H 0105

FePt-based exchange coupled composite media — •Manfred Albrecht — Institute of Physics, Chemnitz University of Technology, 09126 Chemnitz, Germany

In order to continue the areal density increase in magnetic hard disk drives, it is necessary to develop media that support very small bit sizes, while maintaining thermal stability as well as writability of the bits. One potential candidate as a recording layer are L10 chemically ordered FePt alloys which exhibit a huge magnetic anisotropy value. However, the magnetic field required to switch the magnetization of one individual FePt bit typically exceeds the maximum available write field. To solve this so called writability issue in magnetic data storage, a recording concept known as exchange coupled composite (ECC) media aiming to lower the switching field of individual bits was proposed. ECC films consist of a high anisotropy layer coupled to a low anisotropy layer and have been shown to combine both thermal stability and low coercivity for writability. Such ECC structures are also attractive for bit patterned media (BPM), where the bits are individual pillars of magnetic material that are defined by lithography.

In this presentation I will focus on L10 ordered FePt-based ECC thin films and nanostructures fabricated by nanoimprint lithography. Films were transformed to the L10 phase by rapid thermal annealing. I will show that the combination of ECC media with BPM reveals superior properties compared to single layer BPM, as it leads to a significant reduction in the switching field and a substantial narrowing of the switching field distribution.