Thermal stability of magnetic thin films

26 Oct 2014. NUS scientists found a new way to obtain good thermal stability of dynamic magnetic properties for magnetic thin films

Controlling thermal stability of magnetic characteristics is one of the most important but persistent issues for applications using magnetic materials. In many microwave applications, for example, there is a strict requirement for good thermal stability of dynamic magnetic properties of the materials wherein the change of magnetic characteristics in a given range of temperature should be as small as possible.

Recently, a group led by Prof ONG Chong Kim at the Centre of Superconductivity and Magnetic Materials, Department of Physics in NUS has demonstrated that by employing a change in the geometry set up of the thin film growing method such as oblique deposition technique or gradient composition sputtering technique, one can obtain high quality magnetic thin films with excellent thermal stability. In particular, they found that the magnetic thin films grown by employing these techniques show a very small variation of resonance frequency even less than 1% within a temperature range from room temperature to 150 degree Celsius (see Figure). This finding has a great implication as it may open up more opportunity to use magnetic thin films in many applications wherein the environment temperature fluctuates. The group has published their results in a series of academic papers.

Picture shows a schematic view of the oblique deposition system to fabricate magnetic thin films with excellent thermal stability. [Image credit: ONG Chong Kim]

References

1. Phuoc NN, Ong CK. “Anomalous temperature dependence of magnetic anisotropy in gradient-composition sputterred thin films.” Advanced Materials 25 (2013) 980.
2. Chai G, Phuoc NN, Ong CK. “High thermal stability of zero-field ferromagnetic resonance above 5 GHz in ferrite-doped CoFe thin films.” Applied Physics Letters 103 (2013) 042412.
3. Zhong X, Phuoc NN, Liu Y, Ong CK. “Improvement of thermal stability and dynamic magnetic properties of FeCo thin films through using oblique deposition and Co underlayer.” Journal of Magnetism and Magnetic Materials 365 (2014) 8.
4. Zhong X, Phuoc NN, Chai G, Liu Y, Ong CK. “Thermal Stability and Dynamic magnetic properties of FeSiAl films fabricated by oblique deposition.” Journal of Alloys and Compounds 610 (2014) 126.