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Members of the Xiao Group, including Vineetha, Benjamin, Minh, Liam and Haoyu, recently attended the Northeast Quantum Forum 2024, held from October 9-11, 2024 in Durham, New Hampshire. The group showcased their research during the poster session, contributing to the dynamic discussion and advancements in the field of quantum science at the Forum.

About the Northeast Quantum Forum (NEQT) 2024: The NEQT aims to create a collaborative platform for experts and students in quantum science and materials, fostering idea exchange, advancements, and partnerships across the Northeast and beyond. The inaugural event, held October 9-11, 2024, at the University of New Hampshire, focuses on quantum magnets and magnetotransport, with attendees also enjoying New England’s peak autumn scenery. To learn more about the NEQT 2024, please visit here.

Congratulations to Vineetha Bheemarasetty, the 2024 Recipient of the Jun Qi ’03 Ph.D. and Christine Geng Graduate Fellowship in Condensed Matter Experimental Physics!

This fellowship, first awarded in 2021, continues to provide vital support to graduate student research in one of the most exciting areas of physics. The financial support from Jun Qi and Christine Geng has been invaluable and timely in advancing our students’ research in condensed matter physics. We are deeply grateful for their generosity and commitment to fostering scientific discovery.

Congratulations again to Vineetha on this well-deserved recognition!

Brown University Professor of Engineering and Physics Alex Zaslavsky and Physics Professor Gang Xiao, together with Distinguished Senior Engineer Bill Patterson and colleagues at Tufts and CoolCAD Electronics, have been awarded funds from the Army Research Office toward the development of a novel cryogenic camera, an indispensable asset for characterizing superconducting films and circuits.

The grant titled, “Cryogenic magnetic camera that captures real-time trapped flux vortex dynamics in superconducting electronics,” is worth more than $3.4 million over four years.

Scaling up superconducting electronics circuitry to very-large-scale integration (VLSI) levels has historically been constrained by trapped flux vortices in superconducting layers as they are cooled through the critical temperature in a weak residual magnetic field. These trapped vortices impact the circuit margins and, in the worst case, completely disrupt functionality. Existing mitigation schemes are only partially successful and are based on intuition, rather than quantitative understanding.

The group proposes to leverage current magnetic field-sensing work with a redesign of the magnetic camera, optimized for measuring flux vortex dynamics. The final goal is a cryogenic magnetic camera prototype optimized for real-time nondestructive magnetic flux motion imaging in superconducting circuits.

Source: Brown University School of Engineering

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Hoang Minh Cao, a master student researcher from our research group, has been recognized with the Master’s Research Excellence Award by the Physics Department.

Since joining our group in the spring semester of 2023, Minh has made significant contributions to our lab. His research in condensed matter physics, particularly in spintronic materials and devices, has been nothing short of remarkable. His innovative approach extends from material synthesis to exploring their technological applications. Minh has also excelled academically. Minh has been accepted into our PhD program, where he will undoubtedly continue to contribute significantly to our ongoing research initiatives.

Congratulations to Minh on this significant achievement!

Congratulations to Benjamin, Minh and Vincent for receiving their Master’s degrees at this year’s commencement!

Benjamin and Minh will continue their PhD studies within our group. Benjamin and Minh have already made significant research advancements. Their dedication and hard work have been exemplary, and we look forward to their continued contributions to our research.

Vincent has been accepted to UC Riverside’s physics PhD program. He will begin his new academic journey there starting this fall. His achievements in our group have set a strong foundation for his future success.

We extend our heartfelt congratulations to Benjamin, Minh and Vincent. Their hard work, dedication and accomplishments are a testament to their exceptional capabilities and promise for the future.

Congratulations to Liam Mitchell for being awarded the Physics Department’s Award of Excellence as a Graduate Teaching Assistant. This recognition highlights his exceptional dedication and contributions as a Teaching Assistant.

Liam’s commitment to his role as a TA is truly commendable. He consistently demonstrated thorough preparation for his workshop sessions and office hours, ensuring that he was always ready to assist students effectively. The feedback from students has been overwhelmingly positive, reflecting Liam’s impact on their learning journey. His ability to clarify complex concepts and provide support has been greatly appreciated.

Liam is one of the two graduate TAs who received this award this year, underscoring his outstanding performance and dedication. Congratulations, Liam, on this well-deserved honor!

In a recent study, Professor Gang Xiao and his collaborators have explored the potential of emergent magneto-inductance (EML) in the context of miniaturizing magnetic devices without compromising their performance. By focusing on thin films of Permalloy deposited on polycarbonate substrates, they have identified a stepwise magnetic field-induced EML effect that shows promise for practical applications.

Their observations at room temperature reveal a notable inductance variation in these materials, exceeding 1 microhenry (µH). Interestingly, the inductance exhibits a reversal near zero magnetic field, a finding that could have intriguing applications in the design of magnetic devices.

The study investigates how the EML effect varies with changes in frequency, magnetic field steps, and the width of the film. These variations align with theoretical predictions based on the spin motive force, suggesting that the transient motion of domain walls may play a key role in this phenomenon.

This work represents a step toward enhancing the flexibility and efficiency of magnetic devices, opening up a venue into the future possibilities that lie at the intersection of fundamental physics and technological innovation.

Recently, the Xiao Group has made a pivotal breakthrough in understanding the electronic noise of a single skyrmion, a microscopic swirling magnetic texture with potential for next-generation computing technologies. The study, published in Physical Review B, delves into how skyrmions interact with materials disorder and external perturbations, revealing distinct noise signatures across different pinning regimes. This insight is crucial for developing low-noise, reliable skyrmion-based devices, marking a significant step towards harnessing skyrmions for advanced applications in data storage, logic circuits, and beyond.

The Xiao Group has recently published an insightful Perspective article in APL Materials, exploring the fascinating realm of spin textures in synthetic antiferromagnets (SAFs).

Spin textures, including magnetic domain walls and skyrmions, hold immense promise for revolutionizing electronic devices by encoding information bits.

While ferromagnetic films have shown potential in device prototypes, their widespread implementation has been hindered by material-related limitations. However, antiferromagnetic spin textures present a viable solution to many of these challenges, offering a pathway to faster, smaller, more energy-efficient, and robust electronics.

Synthetic antiferromagnets, characterized by multiple magnetic layers separated by spacers, serve as a platform for manipulating the functionality of spin textures using different materials and interface engineering techniques.

In the Perspective article, the authors extensively examine the challenges and opportunities associated with spin textures in synthetic antiferromagnets. They propose potential directions for future research in this exciting field, shedding light on the advantages of spin textures in SAFs compared to their ferromagnetic counterparts. Notably, they highlight the benefits of smaller size, higher mobility, and the vanishing skyrmion Hall effect. The researchers also discuss the potential of utilizing magnetic multilayers that combine both interfacial and interlayer Dzyaloshinskii-Moriya interactions (DMIs), which present a promising avenue for constructing three-dimensional spin textures. Furthermore, they delve into the incorporation of significant interlayer DMIs in SAFs, which can enhance their nontrivial responses to external stimuli.

The authors believe that spin textures possess the potential to revolutionize the landscape of next-generation beyond-CMOS data storage, logic, probabilistic computing, and neuromorphic computing devices. The ongoing advancements in spin textures within SAFs are poised to significantly broaden the scope of spintronic applications.

This Perspective article provides valuable insights and paves the way for future developments in spin textures and their transformative impact on electronic technologies.

This work is supported by the National Science Foundation under Grant No. DMR-2202514.

The 2023 edition of IMPACT Research at Brown magazine describes recent research on magnetic skyrmions from the Xiao Group on P. 45.

“Physics department interim chair Gang Xiao, professor of physics and engineering, is building devices that generate skyrmions—disk-like magnetic swirls in two-dimensional metallic films—that can change their polarity, motion, and size when exposed to a magnetic field or an electric current. Xiao is already using skyrmions to generate truly random numbers, which might be useful in cybersecurity and encryption, yet he has his sights set higher. Arrays and networks of skyrmions, he said, could form the basis for tiny yet incredibly efficient computers.

“If you built a silicon computer that mimics the human brain, you’d need a nuclear power plant to run it. But humans only need about ten watts of energy to power our brains. Skyrmions could bring us a lot closer to that sort of fast, low-power computation”, said Xiao.

IMPACT, an annual publication from the Office of the Vice President for Research at Brown University, illuminates the trailblazing work of researchers who are pushing boundaries in their respective fields. This sixth issue of IMPACT continues its tradition of spotlighting influential research contributing to global advancement.

In a recent gathering of the Physics Department, faculty, staff and students came together to express their heartfelt appreciation for Professor Gang Xiao, who will be stepping down as the Interim Chair of the department on June 30, 2023. The gathering served as an opportunity to recognize Professor Xiao’s exceptional service following the untimely passing of the department’s former chair, Professor Meenakshi Narain. The presence of Brown’s Interim Provost, Professor Lawrence Larson, further highlighted the significance of Professor Xiao’s leadership and service during this challenging period.

Amidst the gathering, Professor Xiao humbly conveyed his sincere gratitude to the entire physics community. He emphasized the vital role played by every member of the department in ensuring a smooth transition after the tragic loss of the department’s beloved Chair Narain. Their dedication and collaboration were pivotal in upholding the department’s mission.

As Professor Xiao concludes his tenure as Interim Chair, he looks forward to dedicating himself to research and teaching. His passion for scientific exploration and discovery, coupled with his commitment to training future scientists and engineers, will be the driving force behind his endeavors moving forward.