Development of nanogranular SmCo5 thin films for ultra-high density magnetic recording

• Applicant: Dr.-Ing. Shalini Sharma
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 577950823

Emerging technologies such as Artificial Intelligence and Internet of Things require and simultaneously have contributed to an exponential rise in data growth. The global data creation is projected to grow to about 400 zettabytes by 2028. Magnetic recording technology will continue to be the mass storage medium of choice for many years to come. Therefore, increasing the areal density of hard disk drives to meet the data storage requirements remains an important challenge. To achieve an ultra-high areal density exceeding 4 Tb/in2, the ferromagnetic grain diameter must be reduced to approximately 4 nm, while maintaining a sufficient signal-to-noise ratio. However, as the grain size is reduced, the magnetization of the grains can easily fluctuate as the magnetocrystalline energy becomes comparable to the thermal energy. The problem can be overcome by using materials with very high magnetocrystalline anisotropy to compensate for the reduced dimensions of the grains. In this proposal, a nanogranular structure of the ultimate material SmCo5 with the highest magnetocrystalline anisotropy will be developed in thin films, as a step towards revolutionizing the magnetic recording media technology. The extremely large anisotropy of the SmCo5 phase of 20 MJ/m3 can lead to ultra-small thermally stable grain sizes of 2.2 nm, which are smaller than the grain sizes possible in the currently used FePt-based recording media. Such small grain diameters can translate into potential 10-fold increase in the areal density of hard disk drives. The goal of this project is to create a media-like microstructure where c-axis textured SmCo5 grains with fine grain sizes and high anisotropy are isolated by a suitable segregant material. The grain size, grain density and intergranular spacing will be tuned in a highly controlled manner to achieve ultra-high areal density. To facilitate the writing or switching of such high-anisotropic grains at lower magnetic fields and temperature, we will develop exchange-coupled composite nanogranular films in the form of bilayer and graded media. This will enable us to tune the switching field of the hard magnetic SmCo5 grains while maintaining the thermal stability of the magnetic bits. With this work, we will develop SmCo5 as the ultimate magnetic storage material available.

• DFG Programme: Research Grants