Patterning of magnetic thin films and multilayers using nanostructured tantalum gettering templates

Area of Science:

• Materials Science
• Thin Film Physics
• Nanotechnology

Background:

• Cobalt oxide (CoO) is nonmagnetic at room temperature and stable up to ~400°C.
• Magnetic cobalt thin films and [Co/Pd] multilayers are crucial for data storage applications.
• Controlling magnetic properties at the nanoscale is essential for advanced technologies.

Purpose of the Study:

• To demonstrate the conversion of nonmagnetic cobalt oxide into magnetic cobalt thin films and multilayers via annealing.
• To investigate the role of tantalum in the reduction process.
• To develop a nanopatterning technique for creating magnetic nanostructures.

Main Methods:

• Annealing nonmagnetic cobalt oxide (CoO) thin films and [CoO/Pd]N multilayers sandwiched between tantalum (Ta) seed and capping layers at 200°C.
• Utilizing the oxygen-gettering property of tantalum for reduction.
• Employing a nanopatterning approach for localized reduction.

Main Results:

• Effective reduction of CoO to ferromagnetic cobalt thin films at 200°C.
• Conversion of nonmagnetic [CoO/Pd]N multilayers to magnetic [Co/Pd]N multilayers with perpendicular magnetic anisotropy.
• Successful local reduction of [CoO/Pd]N multilayers to create nanostructured arrays.

Conclusions:

• Tantalum facilitates the low-temperature reduction of cobalt oxide due to a thermodynamically driven oxygen-gettering mechanism.
• This process enables the fabrication of magnetic [Co/Pd]N multilayers suitable for magnetic data storage.
• The developed nanopatterning technique offers a pathway for creating nanoscale magnetic arrays in various material systems.