China
Africa
Explore chapters and articles related to this topic
Emerging Spintronic Memories
Published in Evgeny Y. Tsymbal, Igor Žutić, Spintronics Handbook: Spin Transport and Magnetism, Second Edition, 2019
Stuart Parkin, Masamitsu Hayashi, Luc Thomas, Xin Jiang, Rai Moriya, William Gallagher
Racetrack memory is a storage-class memory technology proposed by IBM in 2002 [20, 21]. Like magnetic HDDs, racetrack memory stores data within a persistent pattern of magnetic domains that are accessed dynamically for writing, reading, or modification (i.e., changing the state of a domain wall [DW] bit), but unlike mechanical HDDs, it uses no moving mechanical parts. The data pattern is stored as a series of magnetic DWs in a microscopic ferromagnetic wire (the racetrack) and accessed by using current pulses to move the entire pattern, intact, along the wire to reading and writing elements integrated within the device. Each storage element of the device will comprise a writing element, a magnetic racetrack, and a reading element. As the data is stored as magnetic domains, it has the same NV nature as data stored in a magnetic disk drive.
Heusler alloys for spintronic devices: review on recent development and future perspectives
Published in Science and Technology of Advanced Materials, 2021
Kelvin Elphick, William Frost, Marjan Samiepour, Takahide Kubota, Koki Takanashi, Hiroaki Sukegawa, Seiji Mitani, Atsufumi Hirohata
In order to employ the Heusler alloy films in spintronic devices, both advantages and disadvantages need to be considered as listed in Figure 3. Both structural and magnetic properties of the Heusler alloys can be controlled by the substitution of constituent elements of the alloy as detailed in the following sections. For example, the total spin magnetic moments, and the corresponding saturation magnetisation, can be precisely controlled by atomic substitution. Such controllability is useful for spin injection to minimise a stray field for the applications of an HDD read head, an MRAM cell and a magnetic racetrack memory, for instance. These properties also depend on the crystalline ordering of the Heusler alloys. For the half-metallicity, low damping constants and high TC, the perfect crystalline ordering needs to be achieved. Any departure from theoretical prediction on these properties can be attributed to disordering of the alloys. These magnetic properties are important for spin injection, accumulation, operation and detection in spintronic devices. Both structural and magnetic properties of the Heusler alloys are also depend on the lattice matching with substrates and seed layers. A low coercivity and large activation volume can be achieved by removing strain induced by lattice mismatch between them. These magnetic properties are again important for spin transport in devices.
Super-hierarchical and explanatory analysis of magnetization reversal process using topological data analysis
Published in Science and Technology of Advanced Materials: Methods, 2022
Sotaro Kunii, Alexandre Lira Foggiatto, Chiharu Mitsumata, Masato Kotsugi
The microstructures of magnetic domains are critical in characterizing the functions of various advanced magnetic devices. In the next generation of high-speed and high-density information devices, the reliability of data storage and writing speed processes will be determined by changes in microscopic magnetic domain structures [1–4]. Since 0/1 of bit is recorded as positive/negative magnetization, the precise control of the vortex core in magnetic domain structures is key to controlling the information in the racetrack memory or magnetoresistive random access memory (MRAM) of spintronics devices [5–8]. In addition, the magnetic domain structure in artificial spin ice has attracted significant attention for the realization of quantum computers [9–11]. The topological symmetry of magnetic nanowires causes fluctuations in the stability of magnetic moments, resulting in unique orders such as frustrated magnetism. In the motors of next-generation electric vehicles, understanding the magnetization reversal process is essential to reducing iron losses in electromagnetic steel sheets to improve their power generation efficiency [12–14]. Therefore, magnetic materials have a wide range of applications, such as information devices, quantum computing, and electric vehicles. They are extremely important for realizing a sustainable society [15]. Since these macroscopic magnetic functions are achieved by controlling the microscopic magnetic domain structures and stability of the magnetization reversal process, it is essential to develop an analytical method that can realize a hierarchy in materials and explain the origins of certain functions.