Hoang Minh Cao receives physics department’s Master’s Research Excellence Award

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

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.

Liam Mitchell receives physics department’s Award of Excellence as a Graduate Teaching Assistant

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!

New discovery in magnetic materials: a step forward in miniaturizing magnetic devices

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.

Unlocking the secrets of skyrmion noise for future technologies

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.

Xiao group publishes perspective article on spin textures in synthetic antiferromagnets

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.

Research on magnetic skyrmions featured in Brown’s IMPACT magazine

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.

Like traditional silicon computer processors, these devices would still be based on ones and zeros (or, in the case of skyrmions, a larger or smaller size), but the way information flows through the processor would be vastly different. When a skyrmion oscillates its size, it changes the state of its neighbors, creating a cascading effect that is eerily similar to the way neural circuits in the brain function—meaning that this sort of device could make huge strides in computing power while requiring only a small fraction of the energy required by existing 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.

Physics department acknowledges Professor Xiao’s service

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.

Junhang Duan receives physics department’s ScM research excellence award

Junhang Duan, a talented master student researcher from Professor Xiao’s Group, has been recognized with the ScM Research Excellence Award by the Physics department. Her research on the physics of magnetic skyrmion and domain wall motion, conducted under the guidance of Professor Gang Xiao, has earned her this well-deserved recognition.

Upon completing her master’s studies, Junhang will continue her academic journey as a PhD student at Northwestern University, beginning this Fall semester.

Congratulations to Junhang on this significant achievement, and we wish her the best of luck in her future research endeavors at Northwestern!

Professor Xiao gave a lecture for the FCMP Columbia 2023 Spring Series

Professor Xiao gave a lecture for the “Frontiers of Condensed Matter Physics” (FCMP) Columbia 2023 Spring Series on April 3rd, 2023. The lecture, titled “Generating true random numbers with single skyrmions: exploring local dynamics and skyrmion interactions”, is part of a lecture series featuring leading CMP-AMO researchers sharing their latest findings and insights.

About FCMP: Since 2011, Columbia University has been hosting the “Frontiers of Condensed Matter Physics (FCMP) Lectures” to bring in leading CMP/AMO researchers and provide a platform for them to present their latest research to a diverse audience comprising graduate students, postdocs, and senior researchers. The lectures aim to be historically, pedagogically, and intuitively presented to enable even entry-level CMP graduate students to enjoy and gain valuable insights from them.

In response to the ongoing pandemic, the lectures have been moved fully online since 2020, and recordings of the lectures are made available to subscribed students and interested observers from the research community. The FCMP is organized by Professor Yasutomo Uemura of Columbia University. The 2023 Spring series is co-hosted by Professors Philip Kim (Harvard), Pengcheng Dai (Rice), Liuyan Zhao (Michigan), and Weiwei Xie (Michigan State), who circulate flyers among their groups and institutions and recommend speakers. The lecture series promises to be an exciting and informative event for all those interested in the latest developments in condensed matter physics.

Professor Xiao gave an invited talk on single skyrmion true random number generator at APS March Meeting

On March 8, 2023, Professor Xiao gave an invited talk at the APS March Meeting 2023 in Las Vegas, NV. The talk was part of Session M44 on Topological Magnetic Textures and was titled “Single skyrmion true random number generator using local dynamics and interaction between skyrmions”.

During the talk, Professor Xiao discussed the creation of a single skyrmion true random number generator, which utilizes local dynamics, and a multi-skyrmion system whose dynamics is influenced by the interaction between skyrmions. This new physics could have implications for a range of fields, from cryptography to probabilistic computing.

The video recording of Professor Xiao’s talk is available till June 20, 2023 on APS March Meeting website. Access to the recording requires APS March Meeting registration.

This innovative research represents an exciting advancement in the field of topological magnetic textures, and we look forward to seeing how this technology will be utilized in the future.

The research was supported by the National Science Foundation (OMA-1936221).

Fundamental physics and applications of skyrmions: A review

Magnetic skyrmions are tiny magnetic swirls that hold great potential in innovative electronic devices owing to their desirable properties of long-term stability, small size, and highly efficient controllability by various external stimuli. In this recently published review, we address the fundamental physics of the static, global and local dynamic properties of skyrmions and provide an overview of recent advances in computational models that utilize these unique properties. A discussion on the challenges lying ahead is also provided.

For more information, click here.