New Material with Ferroelectricity and Ferromagnetism May Lead to Better Computer Memory
December 21, 2016 | Tokyo Institute of TechnologyEstimated reading time: 2 minutes
Traditional computer memory, known as DRAM, uses electric fields to store information. In DRAM, the presence or absence of an electric charge is indicated either by number 1 or number 0. Unfortunately, this type of information storage is transient and information is lost when the computer is turned off.
Newer types of memory, MRAM and FRAM, use long-lasting ferromagnetism and ferroelectricity to store information. However, no technology thus far combines the two.
To address this challenge, a group of scientists led by Prof. Masaki Azuma from the Laboratory for Materials and Structures at Tokyo Institute of Technology, along with associate Prof. Hajime Hojo at Kyushu University previously at Tokyo Tech, Prof. Ko Mibu at Nagoya Institute of Technology and five other researchers demonstrated the multiferroic nature of a thin film of BiFe1-xCoxO3 (BFCO) (Advanced Materials, "Ferromagnetism at Room Temperature Induced by Spin Structure Change in BiFe1-xCoxO3 Thin Films").
Portions of the BiFeO3 lattice of cycloidal and collinear phases with only Fe ions are shown at left and right, respectively. The arrows indicate the Fe3+ moment direction. The ground state of BiFeO3 had a cycloidal spin structure, which is destabilized by substitution of Co for Fe and at higher temperatures. The spin magnetic moments compensate with each other in the left panel, but canting between neighboring spins leads to the appearance of weak ferromagnetism in the left panel. (Image: Tokyo Institute of Technology)
Multiferroic materials exhibit both ferromagnetism and ferroelectricity. These are expected to be used as multiple-state memory devices. Furthermore, if the two orders are strongly coupled and the magnetization can be reversed by applying an external electric field, the material should work as a form of low power consumption magnetic memory.
Previous scientists had speculated that ferroelectric BFO thin film, a close relative of BFCO, might be ferromagnetic as well, but they were thwarted by the presence of magnetic impurity.
Prof. M. Azuma's team successfully synthesized pure, thin films of BFCO by using pulsed laser deposition to perform epitaxial growth on a SrTiOBiFe1-xCoxO3 (STO) substrate. They then conducted a series of tests to show that BFCO is both ferroelectric and ferromagnetic at room temperature.
Ferroelectric hysteresis loop (left) and magnetic hysteresis loop (right) measured at room temperature indicate the coexistence of ferroelectricity and ferromagnetism. (Image: Tokyo Institute of Technology)
They manipulated the direction of ferroelectric polarization by applying an electric field, and showed that the low-temperature cychloidal spin structure, essentially the same as that of BiFeO3, changes to a collinear one with ferromagnetism at room temperature.
In the future, the scientists hope to realize electrical control of ferromagnetism, which could be applied in low power consumption, non-volatile memory devices.
Suggested Items
Stan Rak: Elevating the Ideas and Insights of IPC's Thought Leaders Program
04/25/2024 | Stanton Rak, SF Rak CompanyAs a member of the IPC Thought Leaders Program (TLP), I am responsible for identifying knowledge-sharing opportunities that can generate ideas and insights that strengthen the IPC community as well as create a sustainable and lasting future for its members. I am delighted to highlight some of my recent contributions as a member of the TLP.
indie Semiconductor Launches Advanced Smart Connectivity Solutions for In-Cabin Applications
04/23/2024 | indie Semiconductorindie Semiconductor, Inc., an Autotech solutions innovator, has introduced a family of new high-performance video converters and retimers to enable in-cabin connectivity applications, including audio and video transport and device interfacing.
The Need for a Holistic Global Sustainability Standard
04/10/2024 | Michael Ford, Aegis SoftwareNo one can deny that the resources of our fragile planet are finite. The environment seems like a third party, subject to constant degradation. We’re acutely aware of the effects of pollution on our climate, and despite our “throw-away” culture, recycling and recovery of materials has remained relatively expensive, even as we use more energy just to survive.
Technica Leads the Way Into Automation and Machine Learning at IPC APEX EXPO 2024
03/28/2024 | Marcy LaRont, PCB007 MagazineAs a significant partner to PCB fabricators since almost the beginning of multilayer boards, Technica USA brings a lot of expertise to the industry. This year’s IPC APEX EXPO show will showcase their biggest booth yet, and a whole lot of information, discussion and demonstration around automation and AI machine learning. In this interview, Jason Perry discusses Technica's plans for the show, and why attendees should stop by.
Airbus to Acquire INFODAS and Strengthen its Cybersecurity Portfolio
03/25/2024 | AirbusAirbus Defence and Space has entered into an agreement to acquire INFODAS, a Cologne-based, German company that provides cybersecurity and IT solutions in the public sector including for defence and critical infrastructures.