
Giant Faraday rotation of cobalt ferrite thin films deposited on silicon substrates for silicon photonic nonreciprocal device applications
Citation
Mario Alberto Serrano-Núñez, Yuya Shoji, and Tetsuya Mizumoto, "Giant Faraday rotation of cobalt ferrite thin films deposited on silicon substrates for silicon photonic nonreciprocal device applications," Applied Physics Express, vol. 13, article number 062002, 2020
Keywords
- Faraday rotation (FR)
- Cobalt ferrite (CFO)
- Thin films
- Silicon substrates
- Nonreciprocal devices
- Silicon photonics
- Magnesium oxide (MgO) buffer layer
- Radiofrequency magnetron sputtering
- Substrate temperature (ST)
- Magnetic easy axis
- In-plane (IP)
- Out-of-plane (OP)
- Optical isolators
- Optical circulators
- Photonic integrated circuits
- Magneto-optical (MO) materials
- Spinel materials
- Wavelength of 1550 nm
- X-ray diffraction (XRD)
- Vibrating sample magnetometer (VSM)
- Magnetic hysteresis loops
Brief
This article demonstrates the growth of crystalline cobalt ferrite thin films on silicon substrates using a magnesium oxide buffer layer, achieving a giant Faraday rotation coefficient and showing that the magnetic easy axis can be tuned by varying the substrate temperature for potential use in silicon photonic nonreciprocal devices.
Summary
This paper reports the successful deposition of crystalline cobalt ferrite (CFO) thin films on silicon substrates using an MgO buffer layer, achieving a giant Faraday rotation coefficient of 25,600 deg cm⁻¹ at 1550 nm. The study also found that varying the substrate temperature during deposition (500-700 °C) allows for the tuning of the magnetic easy axis of the CFO films from in-plane to out-of-plane. This tunability is crucial for the development of silicon photonic nonreciprocal devices like optical isolators and circulators that require specific magnetic anisotropy for operation in TM or TE modes. The achieved Faraday rotation is the largest reported for a thin film on silicon at telecom wavelengths.
Origin: https://sci.bban.top/pdf/10.35848/1882-0786%252Fab8b52.pdf#