Hartmagnetische L10-FePt basierte grossflächige Nanomuster mittels Nanoimprint-Lithografie (PDF)

In our modern world advanced magnetic materials with excellent magnetic properties are getting more and more important. Major areas needed to be mentioned here are for example high performance permanent magnets for electric motors or magnetic data storage media. Further development of existing products or even new applications can only be possible with a continuous optimization of intrinsic and extrinsic material parameters of magnetic materials.
Looking at the temporal development of magnetic data storage devices, it is characterized by a continuous increase of the data storage density, what can be achieved by smaller bit sizes. For continuing this trend and realizing storage densities of 1 TBit/in² bit sizes are needed, which reach their physical limits. Since current magnetic storage media consist of a granular layer and one bit consists of a various number of grains, with the ongoing miniaturization of the bits the bit boundary is getting more and more blurred. This issue can be postponed by the usage of ever smaller grains. An alternative route to optimize the signal to noise ratio is the usage of bit patterned media, where each dot represents a single bit. Depending on the magnetic material used, however, a minimal grain size is given, since the magnetization will become thermally unstable if the grains are too small. This phenomenon is known as the superparamagnetic limit. Hence, for future magnetic storage media a material is needed having an extremely high crystalline anisotropy and hence circumventing this superparamagnetic limit.