Magneto-Optic Nanocrystalline Oxides Fabrication

Full Description

Background:

Magneto-optical Faraday effect is a key property in optics technology. The Faraday is the only way known to make a practical optical diode/isolator. Faraday effect refers to the rotation of linearly polarized light by a material exposed to an external magnetic field. The state of the art optically transparent paramagnet employed in Faraday elements is a single crystal oxide known as Terbium Gallium Garnet (TGG).

Materials that have a high magnetic response to magnetic fields and transparency in the visible spectrum are extremely rare. Rare earth oxides (REOs) are viable candidates but the successful production of REOs has been limited by shortcomings in processing technology.

Prof. Javier Garay and his team at the University of California Riverside have developed a novel, patented technology that circumvents the challenges with processing of REOs using current activated pressure assisted densification (CAP AD) that produces REOs that are transparent and magnetically susceptible. The developed nanocrystalline Dysprosium Oxide (Dy2O3) has a Verdet constant that is 2.25 times larger than TGG.

A nano-Dy2O3 sample processed using CAPAD indicating transparency. The sample is 0.64 mm thick and 19 mm in diameter.

Measured Faraday rotation vs applied magnetic field for both the flint glass reference (0.49 mm thick) and nano-Dy2O3 (0.64 mm thick). 

Advantages

The significant aspects of this technology are:

• A platform technology that produces densified REOs at an optimum temperature and offers precise control of temperature, pressure and time.
• With a Verdet constant that is 2.25 times greater than the state of art, the technology offers the ability to develop REOs that are thinner and offer the same rotation at a given magnetic field; or more importantly the applied magnetic field can be decreases for a given optical rotation. This allows for smaller, cheaper and more portable devices and the use of inexpensive permanent magnets.
• Produces densified REOs quickly (< 20 minutes) compared to single crystal growth methods that require days.

Suggested uses

 Wide array of applications including:

Related Materials

• J.R. Morales et al. Magneto-optical Faraday effect in nanocrystalline oxides. J. of Applied Physics. 109 (2011) - 05/09/2011

Patent Status

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Please review all inventions by Prof. Javier Garay and his team at UCR