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Spin-based devices can reduce energy leakage and thus increase energy efficiency. They have been seen as an approach to overcoming the constraints of CMOS downscaling, specifically, the Magnetic Tunnel Junction (MTJ) which has been the focus of much research in recent years. Its nonvolatility, scalability and low power consumption are highly attrac...
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... the other hand, the results presented in Reference [26] show that VCMA-MeRAMs outperform STT-MRAM in terms of area, speed and energy consumption. Table 1 reproduces some comparisons presented in Reference [44]. However, it should be highlighted that they are developing technologies. ...Similar publications
Continuous downscaling of CMOS technology at the nanometer scale with conventional MOSFETs leads to short channel effects (SCE), increased subthreshold slope (SS), and leakage current, degrading the performance of ICs. We proposed a dual-source vertical tunnel field-effect transistor (TFET) with a steeper subthreshold swing (SS) and superior electr...
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... This offers advantages such as high endurance, fast read and write speeds, and low power consumption. Its compatibility with standard CMOS processes makes it an attractive option for next-generation memory architectures [24]. ...
... SOT-MRAM offers several additional advantages, including fast switching speed, low power consumption, and scalability. Ongoing research is focused on improving the performance and reliability of SOT-MRAM, as well as exploring its integration with existing semiconductor technologies [24]. ...
This paper conducts a comprehensive study on intermittent computing within IoT environments, emphasizing the interplay between different dataflows—row, weight, and output—and a variety of non-volatile memory technologies. We then delve into the architectural optimization of these systems using a spatial architecture, namely IDEA, with their processing elements efficiently arranged in a rhythmic pattern, providing enhanced performance in the presence of power failures. This exploration aims to highlight the diverse advantages and potential applications of each combination, offering a comparative perspective. In our findings, using IDEA for the row stationary dataflow with AlexNet on the CIFAR10 dataset, we observe a power efficiency gain of 2.7% and an average reduction of 21% in the required cycles. This study elucidates the potential of different architectural choices in enhancing energy efficiency and performance in IoT systems.
... Among the spintronics devices, the PMA-MTJ device stands out due to its scalability, high density, and thermal stability, making it preferable for hybrid logic gate designs [11][12][13][14][15][16][17][18]. Various writing mechanisms such as spin-transfer torque (STT) are explored in literature, with STT-MTJ gaining traction due to its commercial viability and simplicity, enabling its application in logic-in-memory (LIM) architecture [19,20]. ...
Complementary Metal Oxide Silicon (CMOS) technology faces a major concern in power dissipation due to the scale-down of technology nodes to the nanoscale. To, resolve this problem, logic-in-memory (LIM) structures are researched as a solution. A spintronics device called magnetic tunnel junction (MTJ) uses less static power than CMOS technology. To improve the energy efficiency of LIM structures, spin-transfer torque based magnetic
tunnel junction (STT-MTJ) and CMOS are used to design digital circuits. In this paper, the design of hybrid AND/ NAND, OR/NOR, and XOR/XNOR logic gate are done by exploring two proposed LIM designs namely LIM1 based on a pre-charge sense amplifier (PCSA) and LIM2 based on a modified version of PCSA (M-PCSA)using the Cadence simulator. This work considers the incorporation of separated transistor logic into the LIM structure to provide separate read and write paths. The results are compared in respect of delay, power, gate count and energy consumption. The proposed LIM1 and LIM2-based AND/NAND, OR/NOR and XOR/XNOR design shows 47.5%, 49.6%, 41.9% and 59.3%, 60.7%, 55.7% lower energy consumption respectively compared to the existing CMOS-based designs. This paper exhibits the design of energy efficient hybrid MTJ/CMOS structures using optimized read/write circuitry and it is appropriate for IoT applications.
... The magnetic tunnel junction (MTJ) sensor has been shown to have the ability to sense magnetic fields at levels as low as tens of pT and have been broadly applied in many important areas such as geomagnetic detection, magnetic anomaly detection, and navigation [1][2][3][4][5][6][7][8][9]. Usually, an MTJ sensor is combined with a voltage amplifier (VA), feedback circuit, and analog-to-digital converters (ADCs) to form a closed-loop magnetometer as a way to increase the measurement range of the MTJ sensor and improve the linearity of the system [10][11][12][13][14]. ...
Magnetic tunnel junction (MTJ) sensors have been one of the excellent candidates for magnetic field detection due to their high sensitivity and compact size. In this paper, we design a magnetometer with in situ magnetic feedback consisting of an MTJ sensor. To analyze and evaluate the detectivity of the MTJ magnetometer, a noise model of the MTJ sensor in the magnetometer without magnetic feedback is first developed. Then, the noise model of the MTJ magnetometer with in situ magnetic feedback is also established, including the noises of the MTJ sensor and the signal conditioning circuit, as well as the feedback circuit. The equivalent noise model of the MTJ magnetometer with in situ magnetic feedback is evaluated through nonlinear fitting for the noise voltage spectrum. Although the noise generated by the MTJ sensor is much greater than that of the signal conditioning circuit, the noise introduced by the feedback coils into the MTJ sensor is slightly more than twice that generated by the MTJ sensor itself. The measurement results show that the detectivity of the MTJ magnetometer with in situ magnetic feedback reaches 526 pT/Hz1/2 at 10 Hz. The equivalent noise analysis method presented in this paper is suitable for the detectivity analysis of magnetometers with magnetic feedback.
... Spintronic devices have been seen as an approach to overcoming the limitation of CMOS downscaling and also can reduce power consumption and thus increase the energy efficiency of the next generation of integrated circuits [13][14][15]. One of the famous spintronic devices is magnetic tunnel junction (MTJ) which can be found in many types of research due to its fascinating features like nonvolatility, scalability, and low power consumption [16][17][18][19]. It is also noteworthy that the manufacturing process of the spintronic device and MTJ is compatible with the manufacturing process of CMOS and CNTFET transistors. ...
Unlike a binary logic system, multi-valued logic (MVL) offers many advantages, such as containing more data than binary. Quaternary logic, the most consistent form with binary logic, is a famous MVL system. This paper proposes a low-cost and nonvolatile quaternary memory based on the hybrid carbon nanotube field effect transistor (CNTFET) and multi-tunnel magnetoresistance magnetic tunnel junction (MTMR-MTJ) logic. The proposed memory benefits from the tunable threshold voltage of CNTFET and the nonvolatility feature MTJ. Simulation results indicate that the proposed memory in this paper offers 41% to 72% lower average power consumption than the previous nonvolatile quaternary memories.
... The progress in deposition and crystal growth technologies has sparked significant interest in multilayer stacks, establishing them as a promising platform for advancing the fields of optical [1][2][3] and spintronic [4][5][6] devices. Magnetic tunnel junctions (MTJs), are multilayer structures consisting of two ferromagnetic layers separated by an insulating barrier, and exhibit multifaceted functionality and efficacy across a broad range of scientific domains, including data storage, sensing, and computing [7][8][9][10][11]. Spin-transfer torque-based magnetic tunnel junctions (STT-MTJs) represent the next generation of MTJs, employing the spin-transfer torque effect to control the magnetization of a ferromagnetic layer. ...
We have developed and optimized two categories of spin-ransfer torque magnetic tunnel junctions (STT-MTJs) that exhibit a high tunnel magnetoresistance ratio, low critical current, high outputpower in the micro-watt range, and auto-oscillation behavior. These characteristics demonstrate the potential of STT-MTJs for low-power, high-speed, and reliable spintronic applications, including magnetic memory, logic, and signal processing. The only distinguishing factor between the two categories, denoted as A-MTJs and B-MTJs, is the composition of their free layers, two CoFeB/0.21 Ta/6 CoFeSiB for A-MTJs and two CoFeB/0.21 Ta/7 NiFe for B-MTJs. Our study reveals that B-MTJs exhibit lower critical currents for auto-oscillation than A-MTJs. We found that both stacks have comparable saturation magnetization and anisotropy field, suggesting that the difference in auto-oscillation behavior is due to the higher damping of A-MTJs compared to B-MTJs. To verify this hypothesis, we employed the all-optical time-resolved magneto-optical Kerr effect technique, which confirmed that STT-MTJs with lower damping exhibited auto-oscillation at lower critical current values. Additionally, our study aimed to optimize the STT-MTJ performance by investigating the impact of the capping layer on the device’s response to electronic and optical stimuli.
... Magnetic tunnel junctions (MTJs) are widely used in electronic storage devices such as magnetic random access memory, analog to digital converters, and sensors [1,2]. The typical structure of an MTJ consists of ferromagnetic/insulator/ferromagnetic layers, as discussed in the supplementary text. ...
In-situ system for metallic multilayer thin films used for magnetic tunnel junction (MTJ) required multi-target system to avoid the formation of impurities which make these devices very costly. In this work, the study was performed to resolve this issue by using a single target system for multilayer formation and impurity phases were dissolved by swift heavy ion (SHI) irradiation. A pristine MgO/Si(1 0 0) and CoFe 2 O 4 /MgO/ZnFe 2 O 4 /Si(1 0 0) (CFMZF) multilayer thin film are prepared via radio frequency (RF) sputtering technique. These structures were irradiated by 75 MeV oxygen-ion fluence (5x10 11 , 1x10 12 , and 5x10 12 ions/cm 2) and 200 MeV silver-ion fluence at 1x10 12 ions/cm 2 for the investigation of structural changes. The high-resolution X-ray diffraction (HRXRD) reveals that MgO thin film has impurity peaks, dissolved via O-ion and Ag-ion irradiation. Further XRD analysis confirms that Ag-ion irradiation dissolves more peaks leaving one small intensity peak of (4 0 0) corresponding to MgO. The multilayer stack of CFMZF irradiated via Ag-ion shows that Mg(OH) 2 phase were completely dissolved and appears only (3 1 1) less intense peak corresponding to the ferrite structure. The findings are also corroborated by cross-sectional Field Emission Scanning electron microscopy of CFMZF multilayer thin film showing damaged layers with Ag-ion irradiation. Therefore, the SHI irradiation technique can be used to dissolve the impurity peaks and improve the interface of the multilayer stacks.
... 5-8 As an application of TMR, magnetic tunnel junctions (MTJs) have become the leading devices for field sensing, nonvolatile MRAM, and spin logic applications. 7,8,[11][12][13] MTJ is a component consisting of a ferromagnet (FM)/spacer/ ferromagnet stack, usually with a TMR value of several hundred or even thousand. 7-10 Traditionally, although four distinct stable magnetic states are possible in an MTJ such as CoFeB/MgO/CoFeB, Published under an exclusive license by AIP Publishing FIG. ...
Magnetic tunnel junction (MTJ) based on van der Waals (vdW) magnetic layers has been found to present excellent tunneling magnetoresistance (TMR) property, which has great potential applications in field sensing, nonvolatile magnetic random access memories, and spin logics. Although MTJs composed of multilayer vdW magnetic homojunction have been extensively investigated, the ones composed of vdW magnetic heterojunction are still to be explored. Here, we use first-principles approaches to reveal that the magnetic heterojunction MTJs have much more distinguishable TMR values than the homojunction ones. In the MTJ composed of bilayer CrI3/bilayer Cr2Ge2Te6 heterojunction, we find there are eight stable magnetic states, leading to six distinguishable electronic resistances. As a result, five sizable TMRs larger than 300% can be obtained (the maximum TMR is up to 620 000%). Six distinguishable memories are obtained, which is two times larger than that of a four-layered homojunction MTJ. The underlying relationships among magnetic state, spin-polarized band structures, and transmission spectra are further revealed to explain the multiple TMR values. We also find that the magnetic states, and thus TMRs, can be efficiently modulated by an external electric field. This study opens an avenue to the design of high-performance MTJ devices based on vdW heterojunctions.
... The progress in deposition and crystal growth technologies has sparked significant interest in multilayer stacks, establishing them as a promising platform for advancing the fields of optical [1][2][3] and spintronic [4][5][6] devices. Magnetic tunnel junctions (MTJs), are multilayer structures consisting of two ferromagnetic layers separated by an insulating barrier, and exhibit multifaceted functionality and efficacy across a broad range of scientific domains, including data storage, sensing, and computing [7][8][9][10][11]. Spin-transfer torque-based magnetic tunnel junctions (STT-MTJs) represent the next generation of MTJs, employing the spin-transfer torque effect to control the magnetization of a ferromagnetic layer. ...
We developed and optimized two novel categories of spin transfer torque magnetic tunnel junctions (STT-MTJs), featuring a high tunnel magnetoresistance (TMR) ratio, low critical current, and out-oscillation behavior, which demonstrates their potential for low-power, high-speed, and reliable spintronic applications such as magnetic memory, logic, and signal processing. The SST-MTJs based on NiFe showed lower critical currents for auto-oscillation as compared to those based on CofeSiB. Using VSM measurements that established comparable saturation magnetization and anisotropy field for both stacks, we attributed this observation to the higher damping of A-MTJs compared to B-MTJs. This hypothesis was verified through the all-optical time-resolved magneto-optical Kerr effect (TRMOKE) technique, which confirmed that STT-MTJs with lower damping exhibited auto-oscillation at lower critical current values. Beside, our study aimed to optimize the STT-MTJ performance, regarding the capping layer's impact on the device's response to electronic and optical stimuli.
... [5][6][7][8][9][10][11][12] A major drawback of MTJs as an integrated circuit element is their small current on/off ratio (i.e., small TMR ratio). If much larger RT-TMR ratios can be achieved, the application ranges of TMR-based devices will significantly expand to very high-density MRAMs based on a three-dimensional architecture, nonvolatile magnetic logics, 13 brain-morphic devices, 14 etc. Some of the authors recently investigated simple Fe/MgO/Fe(001) MTJs with a significantly improved TMR ratio up to 417% and 914% at RT and 3 K, respectively, by fine-tuning the crystallinity near the MgO barrier interfaces. ...
We demonstrate tunnel magnetoresistance (TMR) ratios of up to 631% at room temperature (RT) using CoFe/MgO/CoFe(001) epitaxial magnetic tunnel junctions (MTJs). The TMR ratio increased up to 1143% at 10 K. The large TMR ratios resulted from fine-tuning of atomic-scale structures of the MTJs, such as crystallographic orientations and MgO interface oxidation by interface insertion of ultrathin CoFe and Mg layers, which are expected to enhance the well-known Δ 1 coherent tunneling transport. Interestingly, the TMR oscillation effect, which is not covered by the standard coherent tunneling theory, also became significant. A 0.32-nm period TMR oscillation with increasing MgO thickness dominates the transport in a wide range of MgO thicknesses; the peak-to-valley difference of the TMR oscillation exceeds 140% at RT, which is attributed to the appearance of large oscillatory components in the resistance area product.
... Magnetic tunnel junction (MTJ), a sandwich heterojunction consisting of an extremely thin insulator barrier layer with a thickness of about 0.1 nm between two ferromagnetic sheets, is the core component of magnetic random access memories (MRAM) [1][2][3]. MTJ can be directly used as a storage bit cell by fixing the magnetization direction in one of the two ferromagnetic layers (reference layer) and controlling the magnetization direction in the other ferromagnetic layer (recording layer) [4,5]. The stability of the stored data is determined by magnetic anisotropy (MA). ...
MgO-based magnetic heterostructures with interfacial magnetic anisotropy has attracted increasing attention due to its application in building high-density magnetic random access memories. A large and tunable interfacial magnetic anisotropy constant (Ki) is required for high thermal stability and flexible data writability. In this study, the Ki of Fe/MgO, Fe/Pt/MgO, and Fe/Ir/MgO heterostructures with strains from -4.5% to 4.5% were calculated by ab initio electronic structure calculations. It has been found that the Fe/Pt/MgO and Fe/Ir/MgO where the Pt and Ir monolayers are inserted in the interface possess Ki of 2.415 mJ/m2 and -4.468 mJ/m2, which are much larger by several times than that (0.840 mJ/m2) of the Fe/MgO. In particular, the out-of-plane Ki from the interfacial Pt atoms in Fe/Pt/MgO is as high as 5.978 mJ/m2. The magnetic anisotropy of these structures can be significantly manipulated by strain. Combining second-order perturbation theory, the origin of these behaviors has been analyzed by layer-resolved, orbital-resolved, and k-resolved Ki. The spin-flip terms of dz2/dyz orbitals in the interfacial layer are mainly responsible for the out-of-plane Ki and its variation with strain. This work provides a useful guide for the design of high and tunable magnetic anisotropy in the MgO-based magnetic heterostructures.
