(a) A schematic diagram of a tunnel magnetoresistive device and magnetoresistance. (b) A schematic diagram of the crystal of the metastable body-centered cubic cobalt-manganese alloy studied. (c) A schematic diagram of the face-centered cubic structure, which is one of the thermodynamically stable phases of cobalt-manganese alloys. Credit: Tohoku University
In today’s digital age, hardware innovations that efficiently process massive amounts of data and sensor technologies are in greater demand than ever before. Governments around the world are deploying technological advancements to create smarter societies. Thus, magnetoresistive memory (MRAM) and magnetic sensors have become integral components of the hardware and sensors. Tunnel magnetoresistive devices are predominately used in such devices, exploiting the tunnel magnetoresistance effect in detecting and measuring magnetic fields. Ferromagnetic layers in magnetic tunnel junctions magnetize and produce a low resistance state in alignment. Conversely, when not aligned, the tunneling of electrons becomes less efficient and leads to higher resistance, directly affecting the magnetoresistance ratio that determines the efficiency of the tunneling magnetoresistive devices. While iron-cobalt is a commonly used alloy in tunnel magnetoresistive devices, Tohoku University researchers have discovered enormous magnetoresistance ratios with their recent development of a new material, cobalt-manganese alloys.
Dr. Tomohiro Ichinose and Professor Shigemi Mizukami from Tohoku University focused on the strong magnetic properties of cobalt-manganese alloys, with a body-centered cubic metastable crystal structure, and investigated thermodynamically metastable materials to develop a new material capable of demonstrating similar magnetoresistance ratios. Cobalt-manganese alloys have face-centered cubic or hexagonal crystal structures as thermodynamically stable phases. The metastable body-centered cubic structure exhibits strong magnetism, and by adding a small percentage of iron, Tohoku University’s researchers were able to obtain a magnetoresistance ratio of 350% at room temperature and over 1000% at low temperature, demonstrating similar properties to iron-based magnetic alloys currently in use. The device fabrication involved the sputtering method and a heating process, making it compatible with current industries and providing manufacturers with even more choices in creating tunneling magnetoresistive devices.
Since their discovery, various institutes and companies have invested considerable effort in honing device physics, materials, and processes. Tohoku University’s latest groundbreaking development sets an alternative direction of travel for future improvements in the field. To learn more, refer to Journal of Alloys and Compounds.
More information:
Tomohiro Ichinose et al, Large tunnel magnetoresistance in magnetic tunnel junctions with magnetic electrodes of metastable body-centered cubic CoMnFe alloys, Journal of Alloys and Compounds (2023). DOI: 10.1016/j.jallcom.2023.170750
Denial of responsibility! TechCodex is an automatic aggregator of the all world’s media. In each content, the hyperlink to the primary source is specified. All trademarks belong to their rightful owners, and all materials to their authors. For any complaint, please reach us at – [email protected]. We will take necessary action within 24 hours.
Jessica Irvine is a tech enthusiast specializing in gadgets. From smart home devices to cutting-edge electronics, Jessica explores the world of consumer tech, offering readers comprehensive reviews, hands-on experiences, and expert insights into the coolest and most innovative gadgets on the market.
