Spectroscopic Decomposition Reveals Mangetization Mechanism in Multiferrroic Lutetium Iron Oxide Superlattices

Published December 29, 2020

Left: Crystal structure of the (3,1) super-lattice. Right: Interface magnetic circular dichroic spectra

Using electric fields as a switch to control the magnetism of a material is one of the goals behind the study of multiferroics. This work explores the microscopic origins of high temperature magnetism in one such material through the use of optical techniques in high magnetic fields, an approach that could help researchers understand magnetism in a large class of materials.

What did scientists discover?

MagLab users developed a method for extracting interface optical spectra and magnetization in multiferroic superlattices. They employed these techniques to a room-temperature multiferroic superlattice made of layers of LuFeO₃ and LuFe₂O₄ revealing the mechanism for enhanced magnetization and high Curie temperature (above room temperature) in this system.

Why is this important?

Understanding the inner workings of multiferroic interface materials is in its infancy. This spectroscopic decomposition method is a powerful means to learn about how superlattices function via site-specific information gathered directly at the functional interfaces. Opportunities exist to exploit interface materials to advance spintronics and photonics devices. As such, there is broad utility for techniques that reveal interface dynamics that reaches well beyond research into the behavior of multiferroics.

Who did the research?

S. Fan¹, H. Das², A. Rébola³, K. Smith⁴, J. Mundy⁵ , C. Brooks⁵, M. Holtz⁶, D. Muller⁶, C. Fennie⁶, R. Ramesh⁷, D. Schlom⁶, S. McGill⁸, and J. Musfeldt^1,4

¹University of Tennessee, Physics; ²Tokyo Institute of Technology; ³Instituto de Física Rosario-CONICET; ⁴University of Tennessee, Chemistry; ⁵Harvard University, Physics; ⁶Cornell University; ⁷University of California, Berkeley; ⁸National MagLab

Why did they need the MagLab?

The MagLab's unique 25T split helix magnet was crucial because it provides direct optical access to the sample in magnetic field. The high coercivity of these superlattices also requires a large ±25 T field to close the hysteresis loop (see Fig c).

Details for scientists

View or download the expert-level Science Highlight, Site-specific Spectroscopic Measurement of Spin and Charge in (LuFeO₃)_m/(LuFe₂O₄)₁ Multiferroic Superlattices
Read the full-length publication, Site-specific spectroscopic measurement of spin and charge in (LuFeO₃)_m/(LuFe₂O₄)₁ multiferroic superlattices, in Nature Communications

Funding

This research was funded by the following grants: J. L. Musfeldt (DOE, DE-FG02-45201ER45885), G.S. Boebinger (NSF DMR-1157490, NSF DMR-1644779), S. McGill (NSF, DMR-1644779, DMR-122921), D. Schlom (DOE, DE-SC0002334), D. Muller (NSF, DMR-1719875), H. Das (JSPS, 19K05246 ), and A. Rébola, C. Fennie (NSF, DMR-1539918)

For more information, contact Tim Murphy.