Approaching the Magnetic Singularity
June 21, 2019 | MITEstimated reading time: 5 minutes
"The interesting question here is whether or not the singular angular magnetoresistance can be widely observed in magnetic materials and, if this feature can be ubiquitously observed, what is the key ingredient for engineering the materials with this effect," Suzuki says.
The theoretical model indicates that the singular response may indeed be found in other materials and predicts material properties beneficial for realizing this feature. One of the important ingredients is an electronic structure with a small number of free charges, which occurs in a point-like electronic structure referred to as nodal. The material in this study has so-called Weyl points that achieve this. In such materials, the allowed electron momenta depends on the configuration of the magnetic order. Such control of the momenta of these charges by the magnetic degree of freedom allows the system to support switchable interface regions where the momenta are mismatched between domains of different magnetic order. This mismatch also leads to the large increase in resistance observed in this study.
This analysis is further supported by the first-principles electronic structure calculation performed by Jianpeng Liu, research assistant professor at the HKUST, and Balents. Using more traditional magnetic elements such as iron or cobalt, rather than rare-earth cerium, may offer a potential path to higher temperature observation of the singular angular magnetoresistance effect. The study also ruled out a change in the arrangement of the atoms, called a structural phase transition, as a cause of the change in resistivity of the cerium-based material.
Kenneth Burch, graduate program director and associate professor of physics at Boston College, whose lab investigates Weyl materials, notes: “The discovery of remarkable sensitivity to magnetic angle is a completely unexpected phenomena in this new class of materials. This result suggests not only new applications of Weyl semimetals in magnetic sensing, but the unique coupling of electronic transport, chirality and magnetism.” Chirality is an aspect of electrons related to their spin that gives them either a left-handed or right-handed orientation.
The discovery of this sharp but narrowly confined resistance peak could eventually be used by engineers as a new paradigm for magnetic sensors. Notes Checkelsky, “One of the exciting things about fundamental discoveries in magnetism is the potential for rapid adoptions for new technologies. With the design principles now in hand, we are casting a wide net to find this phenomena in more robust systems to unlock this potential.”
This research was supported in part by the Gordon and Betty Moore Foundation and the National Science Foundation.
Page 2 of 2Suggested Items
Material Insight: The Dielectric Constant of PCB Materials
05/17/2024 | Dr. Preeya Kuray -- Column: Material InsightIn the world of PCB design, miniaturization can be achieved by using low dielectric constant (Dk) materials. Low Dk materials can allow for a reduction in thickness while maintaining a given trace width, leading to lower transmission loss and higher density circuitry.
IPC APEX EXPO: Some Thoughts About Growth
05/16/2024 | Dan Feinberg, I-Connect007After two and a half days of wandering the aisles at IPC APEX EXPO 2024, for the first time, I almost felt like I was exploring CES. There were so many booths and exhibits that I could describe, but I’d like to focus on the growth and huge value of this event, which has expanded well beyond just the growing and impressive exhibit show floor.
The Shaughnessy Report: Unlock Your High-speed Material Constraints
05/15/2024 | Andy Shaughnessy -- Column: The Shaughnessy ReportThe world of PCB materials used to be a fairly simple one. It was divided into two groups: the “traditional” laminates, often called FR-4, and the high-speed laminates developed especially for high-speed PCBs. These were two worlds that usually didn’t collide. But then traditional laminates started getting better, and high-speed designers and design engineers took notice and started to reconsider what FR-4 could be used for.
Breaking High-speed Material Constraints: Design007 Magazine — May 2024
05/14/2024 | I-Connect007 Editorial TeamDo you need specialty materials for your high-speed designs? Maybe not. Improvements in resins mean designers of high-speed boards can sometimes use traditional laminate systems instead of high-speed materials, saving time and money while streamlining the fab process. In the May 2024 issue of Design007 Magazine, our contributors explain how to avoid overconstraining your materials when working with high-speed boards.
Indium Experts to Present at Electronics in Harsh Environments SMTA Conference
05/13/2024 | Indium Corporationndium Corporation Technical Manager for Europe, Africa, and the Middle East, Karthik Vijay, will deliver a technical presentation and Indium Corporation Senior Technologist, Dr. Ronald Lasky, will deliver both a workshop and technical presentation at the Electronics in Harsh Environments SMTA Conference on May 14-16 in Copenhagen, Denmark.