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The quantum well (QW) realizes new functionalities due to the discrete electronic energy levels formed in the well-shaped potential. Magnetic tunnel junctions (MTJs) combined with a quasi-QW structure of Cr/ultrathin-Fe/MgAlO(001)/Fe, in which the Cr quasi-barrier layer confines up-spin electrons to the Fe well, are prepared with perfectly lattice-matched interfaces and atomic layer number control. Resonant peaks are clearly observed in the differential conductance of the MTJs due to the formation of QWs. Furthermore, enhanced tunnel magnetoresistance (TMR) peaks at the resonant bias voltages are realized for the MTJs at room temperature, i.e., it is observed that TMR ratios at specific and even high bias-voltages ( ) are larger than zero-bias TMR ratios for the MTJs with odd Fe atomic layers, in contrast to the earlier experimental studies. In addition, a new finding in this study is unique sign changes in the temperature coefficient of resistance (TCR) depending on the Fe thickness and , which is interpreted as a signature of the QW formation of Δ symmetry electronic states. The present study suggests that the spin-dependent resonant tunneling via the QWs formed in Cr/ultrathin-Fe/MgAlO/Fe structures should open a new pathway to achieve a large TMR at practically high .
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http://dx.doi.org/10.1002/advs.201901438 | DOI Listing |
ACS Appl Mater Interfaces
August 2025
Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France.
Discovering an efficient spintronic semiconductor workhorse with dual host capabilities as a channel and spin valve barrier remains one of the most elusive endeavors toward the development of spin-logic circuits. Graphene paved the way for two-dimensional (2D) materials, yet engineering a controlled band gap in it remains a challenge. Black phosphorus (BP) was recently unveiled as a potential candidate in the realm of 2D semiconductors, with carrier mobilities among the largest reported for a 2D material and a low spin-orbit coupling reminiscent of graphene.
View Article and Find Full Text PDFNanomaterials (Basel)
August 2025
School of Materials and Energy, Southwest University, Chongqing 400715, China.
Magnetic tunnel junctions (MTJs) are pivotal for spintronic applications such as magneto resistive memory and sensors. Two-dimensional van der Waals heterostructures offer a promising platform for miniaturizing MTJs while enabling the twist-angle engineering of their properties. Here, we investigate the impact of twisting the insulating barrier layer on the performance of a van der Waals MTJ with the structure graphene/1T-VSe/h-BN/1T-VSe/graphene, where 1T-VSe serves as the ferromagnetic electrodes and the monolayer h-BN acts as the tunnel barrier.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2025
Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden.
We report a robust half-metallic interface state in the CrI/2H-WTe van der Waals (vdW) heterostructure, exhibiting 100% spin polarization and an extraordinary magnetoresistance exceeding 1 × 10%. These unique properties position the CrI/2H-WTe configuration as an exceptional candidate for applications in data storage, spintronics, and spin caloritronics. By designing a device incorporating CrO electrodes, we model charge and spin transport in this heterostructure and analyze the thermal properties under parallel (PM) and antiparallel (APM) magnetization states.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
A van der Waals (vdW) multiferroic tunnel junction (MFTJ) with tunneling electroresistance (TER) and tunneling magnetoresistance (TMR) effects has emerged as a promising candidate for nonvolatile and multifunctional memory devices. However, simultaneously achieving giant TER and TMR ratios still faces significant hurdles. Here, a ScCO/FeBr multiferroic heterostructure is theoretically designed.
View Article and Find Full Text PDFNanoscale
August 2025
Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
Magnetic tunnel junctions (MTJs) are the elemental devices for advanced spintronic technologies, where tunneling magnetoresistance (TMR) serves as one of the key performance metrics. Here, we used the topologically nontrivial magnetic insulator CrVI and magnetic metal FeGeTe to fabricate CrVI/FeGeTe heterojunctions and FeGeTe/CrVI/FeGeTe MTJs. In the heterojunctions, the addition of CrVI led to a 180% coercive field enhancement of FeGeTe near the Curie temperature () of CrVI, which originated from the antiferromagnetic coupling between them.
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