Crystallization of high gyrotropy garnets with decreasing thermal processing budgets as analyzed by electron backscatter diffraction

Karthik Srinivasan, Nicholas C.A. Seaton, Ruoming Peng, Mo Li, Bethanie J.H. Stadler

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Rare-earth iron garnets with large magnetic gyrotropy, made with reduced thermal budgets, are ideal magneto-optical materials for integrated isolators. However, reduced thermal budgets impact Faraday rotation by limiting crystallization, and characterization of crystallinity is limited by resolution or scannable area. Here, electron backscatter diffraction (EBSD) is used to measure crystallinity in cerium substituted yttrium- and terbium-iron garnets (CeYIG and CeTbIG) grown on planar Si, crystallized using one-step rapid thermal processes, leading to large Faraday rotations > -3500 °/cm at 1550 nm. Varying degrees of crystallinity are observed in planar Si and patterned Si waveguides, and specific dependences of crystallite size are attributed to the nucleation/growth processes of the garnets and the lateral dimensions of the waveguide. On the other hand, a low thermal budget alternative-exfoliated CeTbIG nanosheets-are fully crystalline and maintain high Faraday rotations of -3200 °/cm on par with monolithically integrated thin film garnets.

Original languageEnglish (US)
Pages (from-to)357-367
Number of pages11
JournalOptical Materials Express
Volume13
Issue number2
DOIs
StatePublished - Feb 1 2023

Bibliographical note

Funding Information:
Acknowledgements. This work was carried out with support from the Division of Electrical, Communications and Cyber Systems in the National Science Foundation under award number ECCS-2130207. Parts of this work were carried out in the Characterization Facility and the Minnesota Nano Center, University of Minnesota, which receives partial support from the NSF through the MRSEC (Award Number DMR-2011401), and the National Nanotechnology Coordinated Infrastructure (NNCI) program under Award Number ECCS-2025124. K.S. would also like to acknowledge the support of Dr. Jason Myers for help with STEM measurements.

Funding Information:
Division of Electrical, Communications and Cyber Systems (2130207, 2025124); Division of Materials Research (2011401).

Publisher Copyright:
© 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

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