Review
Computer Science, Information Systems
Hao Cai, Bo Liu, Juntong Chen, Lirida Naviner, Yongliang Zhou, Zhen Wang, Jun Yang
Summary: This study reviews the latest techniques in in-memory computing, focusing on the design schemes of spin-transfer torque-MRAM. It points out the limitations and challenges of in-MRAM computing, offering potential methods to overcome these issues. The study also considers design technology co-optimization from the IMC perspective.
SCIENCE CHINA-INFORMATION SCIENCES
(2021)
Article
Materials Science, Multidisciplinary
Sk. Ziaur Rahaman, Yao-Jen Chang, Yu-Chen Hsin, Shan-Yi Yang, Hsin-Han Lee, I. -Jung Wang, Guan-Long Chen, Yi-Hui Su, Jeng-Hua Wei, Shyh-Shyuan Sheu, Wei -Chung Lo, Duan-Li Deng, Shih-Chieh Chang
Summary: The generation of torques in heavy metal and ferromagnet heterostructures in SOT-MRAM makes them attractive for magnetic memory technology. However, the current manufacturing tools present major challenges for etching in SOT-MRAM. In this study, we experimentally investigated two different etching recipes, CF-Etch and NH-Etch, and their effects on the performance of Ta/CoFeB/MgO/Ta magnetic film stacks for SOT-MRAM development.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Computer Science, Information Systems
Yinglin Zhao, Jianlei Yang, Bing Li, Xingzhou Cheng, Xucheng Ye, Xueyan Wang, Xiaotao Jia, Zhaohao Wang, Youguang Zhang, Weisheng Zhao
Summary: To address the performance and efficiency issues of running large-scale datasets on traditional computing systems, a NAND-SPIN-based PIM architecture is proposed for efficient convolutional neural network (CNN) acceleration. A straightforward data mapping scheme is employed to improve parallelism and reduce data movements. Experimental results demonstrate that the approach achieves similar to 2.6x speedup and similar to 1.4x improvement in energy efficiency compared to state-of-the-art PIM solutions.
SCIENCE CHINA-INFORMATION SCIENCES
(2023)
Article
Engineering, Multidisciplinary
Prashanth Barla, Vinod Kumar Joshi, Somashekara Bhat
Summary: A novel self write-terminated driver is proposed for hybrid spin transfer torque-magnetic tunnel junction (STT-MTJ)/CMOS circuits, which reduces the total energy required for writing process noticeably. The driver is also integrated with a hybrid full adder to demonstrate its potential application in low-power VLSI circuits.
AIN SHAMS ENGINEERING JOURNAL
(2021)
Article
Physics, Applied
A. G. Buzdakov, P. N. Skirdkov, K. A. Zvezdin
Summary: This study investigates the phase diagram of the easy-cone magnetic state in spin-torque diodes with interfacial perpendicular magnetic anisotropy. It is found that the increase of the magnetostatic field expands the phase diagram. The influence of the orientation of the nanopillar ellipticity on the phase diagrams is investigated, and the dynamic properties and rectification efficiency of the STD under microwave current injection are considered.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Applied
Chikako Yoshida, Tomohiro Tanaka, Tadashi Ataka, Minoru Hoshina, Atsushi Furuya
Summary: This study investigates the magnetic field-free switching of a three-terminal perpendicular magnetic tunnel junction using spin-orbit torque and spin-transfer torque, driven by voltage-controlled magnetic anisotropy. By optimizing the voltage pulse configuration, high success rate of switching is achieved, with lower power consumption compared to STT-alone writing. Additionally, SOT-STT writing shows greater potential for practical use compared to external magnetic field-assisted SOT writing.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Daniel Sanchez Hazen, Stephane Auffret, Isabelle Joumard, Laurent Vila, Liliana D. Buda-Prejbeanu, Ricardo C. Sousa, Lucian Prejbeanu, Bernard Dieny
Summary: This paper presents the first experimental demonstration of double magnetic tunnel junctions with a magnetically switchable assistance layer, showing that the figure of merit of STT-MRAM cells can be increased by a factor of 4 compared to conventional stacks. Optimization of the assistance layer can maximize the benefits of this concept, as highlighted by numerical simulations provided in the study.
Article
Physics, Condensed Matter
Reza Daqiq
Summary: The study predicts an improvement in thermal spin-transfer torque in magnetic tunnel junctions by introducing anti-reflective Fabry-Perot MTJs. The presence of anti-reflective regions results in a boxcar transmission function in the AR-FPMTJ device, with the TSTT magnitude almost six times greater than in superlattice MTJs, suggesting a novel application in the field of spintronics.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Physics, Multidisciplinary
Yudong Zhuo, Wenlong Cai, Daoqian Zhu, Hongchao Zhang, Ao Du, Kaihua Cao, Jialiang Yin, Yan Huang, Kewen Shi, Weisheng Zhao
Summary: This study reveals the role of field-like torque (FLT) in spin-orbit torque (SOT) driven magnetization reversal. The results show that the promotion or suppression of switching depends on the relative direction of FLT and spin polarization. Furthermore, the FLT modulates the switching speed and power consumption by affecting the work done by the damping-like torque, leading to two different reversal paths.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Physics, Applied
Chaoliang Zhang, Yutaro Takeuchi, Shunsuke Fukami, Hideo Ohno
Summary: In this study, we investigate the magnetization switching using a combination of STT and SOT, finding that SOT allows for fast switching of magnetization and STT eliminates the need for an external field. The results show that in the short pulse regime, the Type X structure achieves a switching current one-fourth smaller than the Type Y structure at 200 ps.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Prashanth Barla, Vinod Kumar Joshi, Somashekara Bhat
Summary: In this study, the spin-Hall effect (SHE)-assisted spin transfer torque (STT) switching mechanism in a three-terminal MTJ device was investigated. Hybrid logic gates based on a combination of p-MTJ and heavy metal materials were designed and evaluated for performance, showing lower power consumption, delay, and device count compared to conventional CMOS gates. This indicates that SHE-assisted STT MTJ/CMOS logic gates are nonvolatile and more efficient in terms of power and space utilization.
JOURNAL OF COMPUTATIONAL ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Jinwu Wei, Xiao Wang, Baoshan Cui, Chenyang Guo, Hongjun Xu, Yao Guang, Yuqiang Wang, Xuming Luo, Caihua Wan, Jiafeng Feng, Hongxiang Wei, Gen Yin, Xiufeng Han, Guoqiang Yu
Summary: Synthetic antiferromagnets (SAFs) show potential in next-generation spintronic devices due to zero net magnetization and high thermal stability, despite typically requiring an in-plane effective magnetic field. A new study demonstrates field-free switching in an all-SAF system with significantly reduced net magnetization, showing robustness up to approximately 460 K.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
A. Meo, S. Sampan-a-pai, P. B. Visscher, R. Chepulskyy, D. Apalkov, J. Chureemart, P. Chureemart, R. W. Chantrell, R. F. L. Evans
Summary: The study investigates the spin transfer torque switching dynamics in CoFeB/MgO/CoFeB magnetic tunnel junctions using atomistic simulations based on Slonczewski's model. The results demonstrate a magnetization reversal driven by the combination of coherent and nonuniform excitation modes, affected by factors such as current density, temperature, and structural imperfections. This deeper understanding can be valuable for spin transfer torque dynamics in nanoscale devices.
Article
Computer Science, Hardware & Architecture
Prashanth Barla, Vinod Kumar Joshi, Somashekara Bhat
Summary: In this paper, a power-efficient self-write-terminated hybrid full-adder (SWTHFA) is proposed, which utilizes a self-write-terminated write driver and an improved sense amplifier. The hybrid spin transfer torque-magnetic tunnel junction (STT-MTJ)/CMOS circuit based on logic-in-memory architecture is used to design the SWTHFA. The proposed SWTHFA demonstrates significant improvement in power saving, output response, and read and write power delay product compared to conventional hybrid full-adder.
JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS
(2022)
Article
Computer Science, Hardware & Architecture
Bayartulga Ishdorj, Taehui Na
Summary: Most IoT devices require long battery life for mobility and achieve optimal battery lifetime in standby mode. Nonvolatile flip-flop (NVFF) allows complete power termination in standby mode, and STT-MTJ-based NVFF designs have been studied to enable zero standby power consumption. Existing designs succeed in achieving target restore yield in the upper threshold voltage region, but degrade in subthreshold voltage region. This study proposes and analyzes four different STT-MTJ-based NVFF designs that operate in the subthreshold voltage region, with one design achieving target restore yield using pMOS body biasing and a transistor scale-up strategy.
IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS
(2023)
Article
Chemistry, Physical
L. T. Hudson, J. P. Cline, A. Henins, M. H. Mendenhall, C. I. Szabo
RADIATION PHYSICS AND CHEMISTRY
(2020)
Article
Materials Science, Characterization & Testing
David R. Black, Marcus H. Mendenhall, Craig M. Brown, Albert Henins, James Filliben, James P. Cline
POWDER DIFFRACTION
(2020)
Article
Materials Science, Multidisciplinary
Abhishek Srivastava, Kayla Cole, Alicia Wadsworth, Thomas Burton, Claudia Mewes, Tim Mewes, Gregory B. Thompson, Ronald D. Noebe, Alex M. Leary
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2020)
Article
Physics, Multidisciplinary
Behrouz Khodadadi, Anish Rai, Arjun Sapkota, Abhishek Srivastava, Bhuwan Nepal, Youngmin Lim, David A. Smith, Claudia Mewes, Sujan Budhathoki, Adam J. Hauser, Min Gao, Jie-Fang Li, Dwight D. Viehland, Zijian Jiang, Jean J. Heremans, Prasanna Balachandran, Tim Mewes, Satoru Emori
PHYSICAL REVIEW LETTERS
(2020)
Article
Materials Science, Multidisciplinary
Takuma Nakano, Bhuwan Nepal, Yoshitomo Tanaka, Shuang Wu, Kyotaro Abe, Gary Mankey, Tim Mewes, Claudia Mewes, Takao Suzuki
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2020)
Article
Physics, Applied
Sudhir Regmi, Zhong Li, Abhishek Srivastava, Rabin Mahat, Shambhu Kc, Ankur Rastogi, Zbigniew Galazka, Ranjan Datta, Tim Mewes, Arunava Gupta
Summary: The research shows that the growth of NiFe2O4 thin films on MgGa2O4 and ZnGa2O4 substrates varies significantly, with films grown on ZnGa2O4 substrate having near perfect matching and almost no strain, maintaining their cubic structure; while films grown on MgGa2O4 substrate exhibit significant strain.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Marcus H. Mendenhall, David Black, Donald Windover, James P. Cline
Summary: The difference in the diffracted intensity of sigma- and pi-polarized components in X-ray powder diffraction is traditionally treated based on dipole scattering, but new equations are presented in this study using dynamical diffraction theory for monochromator crystals. The predicted intensities of X-ray powder diffraction patterns may change when using nearly perfect crystal incident-beam monochromators, especially far from 2 theta = 90 degrees. Experimental data confirms the need for dynamical polarization correction in certain systems.
ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES
(2021)
Article
Physics, Applied
Maxwell Li, Anish Rai, Ashok Pokhrel, Arjun Sapkota, Claudia Mewes, Tim Mewes, Di Xiao, Marc De Graef, Vincent Sokalski
Summary: Through a combination of micromagnetic theory and Lorentz transmission electron microscopy, the substructures of magnetic domain walls in multi-layers have been examined, revealing the conditions for their presence and enabling the formation of a magnetic phase diagram. Additionally, it has been discovered that reduced thickness favors the formation of Q = ±1 substructures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Jonathan J. Denney, Gerard S. Mattei, Marcus H. Mendenhall, James P. Cline, Peter G. Khalifah, Brian H. Toby
Summary: This article presents a new methodology that uses the fundamental parameters approach to describe a laboratory powder diffraction instrument. It allows for the robust determination of peak shapes directly from the physical description of the instrument. This new method can be used for instrument characterization and sample broadening characterization without the need for a standard to determine the instrument profile function.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2022)
Article
Instruments & Instrumentation
Valeria Lauter, Kang Wang, Tim Mewes, Artur Glavic, Boris Toperverg, Mahshid Ahmadi, Badih Assaf, Bin Hu, Mingda Li, Xinyu Liu, Yaohua Liu, Jagadeesh Moodera, Leonid Rokhinson, Deepak Singh, Nian Sun
Summary: M-STAR is a next generation polarized neutron reflectometer with advanced capabilities for nanoscience and spintronics studies. It enables improved grazing incidence diffraction measurements and opens new possibilities for probing near-surface dynamics.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Materials Science, Multidisciplinary
Ashok Pokhrel, Bhuwan Nepal, Upama Karki, Arjun Sapkota, Anish Rai, Sara Bey, Tim Mewes, Claudia Mewes
Summary: This article investigates the influence of layer dependent second-order perpendicular anisotropy on higher-order anisotropies in thin films using a macrospin model. The study finds that the origin of the fourth-order anisotropy is linked to the layer-wise variation of magnetization direction, resulting in a dependence on field strength and exchange stiffness. Furthermore, it is observed that the apparent fourth-order anisotropy increases with decrease in exchange stiffness.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Sujan Budhathoki, Arjun Sapkota, Ka Ming Law, Smriti Ranjit, Gregory M. Stephen, Don Heiman, Michelle E. Jamer, Tim Mewes, Adam J. Hauser
Summary: This study reports the magnetic and magnetodynamic properties of strained epitaxial FeGe thin films on Ge(111) substrates, highlighting the generation of orbital moment in tensile-strained FeGe and the impact of in-plane tensile strain on magnetic transition temperature. X-ray magnetic circular dichroism shows partially quenched atomic orbitals in the films, indicating potential utility of strained FeGe in spintronic applications.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Prabandha Nakarmi, Alicia Koenig, David Tweddle, Kayla Cole-Piepke, Alex M. Leary, Ronald D. Noebe, Gregory B. Thompson, Claudia Mewes, Tim Mewes
Summary: The magnetic and structural characterization of Co75.4Fe2.3Mn2.3Nb4Si2B14 (nominal) nanocomposite thin films and compositional derivatives were studied. The samples were analyzed using transmission electron microscopy and atom probe tomography (APT), and the magnetization dynamics were studied using vibrating sample magnetometry (VSM) and ferromagnetic resonance (FMR) spectroscopy. It was found that FMR spectroscopy was sensitive to the different phases and morphologies present in the samples.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Instruments & Instrumentation
Marcus H. Mendenhall, James P. Cline, Csilla I. Szabo, Albert Henins
Summary: The NIST silicon lattice comparator is an instrument that has been used since the 1970s to measure the difference in lattice spacing between high-quality silicon specimens. Recent upgrades have improved its stability, reduced settling time, and minimized the need for operator intervention.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Materials Science, Multidisciplinary
Shuang Wu, David A. Smith, Prabandha Nakarmi, Anish Rai, Michael Clavel, Mantu K. Hudait, Jing Zhao, Claudia Mewes, Tim Mewes, Satoru Emori
Summary: This study investigates room-temperature magnetic relaxation in polycrystalline Fe films. It is found that the intrinsic Gilbert damping parameter remains unchanged regardless of the microstructural properties of the Fe films, contrary to intuition. This suggests that the room-temperature intrinsic Gilbert damping in Fe films is primarily determined by the bcc crystal structure within the nanoscale grains, with limited effects from grain boundaries and film roughness. In addition, the in-plane FMR linewidths of the Fe films exhibit nonlinear frequency dependencies, indicating the presence of strong extrinsic damping.
