A magnetic tunnel junction with a perpendicular magnetic easy-axis (p-MTJ) is a key device for spintronic non-volatile magnetoresistive random access memory (MRAM). Co-Fe-B alloy-based p-MTJs are being developed, although they have a large magnetisation and medium perpendicular magnetic anisotropy (PMA), which make it difficult to apply them to a future dense MRAM. Here, we demonstrate a p-MTJ with an epitaxially strained MnGa nanolayer grown on a unique CoGa buffer material, which exhibits a large PMA of more than 5 Merg/cm(3) and magnetisation below 500 emu/cm(3); these properties are sufficient for application to advanced MRAM. Although the experimental tunnel magnetoresistance (TMR) ratio is still low, first principles calculations confirm that the strain-induced crystal lattice distortion modifies the band dispersion along the tetragonal c-axis into the fully spin-polarised state; thus, a huge TMR effect can be generated in this p-MTJ.
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http://dx.doi.org/10.1038/srep30249 | DOI Listing |
Materials (Basel)
January 2025
Laboratory for Heteroepitaxial Growth of Functional Materials & Devices, Department of Chemical & Biological Engineering, State University of New York (SUNY) at Buffalo, Buffalo, NY 14260, USA.
This study analyzes the calculation of the critical current density by means of Bean's critical state model, using the equation formulated by Gyorgy et al. and other similar equations derived from it reported in the literature. While estimations of using Bean's model are widely performed, improper use of different equations with different magnetic units and pre-factors leads to confusion and to significant errors in the reported values of .
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Physics, The University of Western Australia, Perth, WA 6009, Australia.
The capture of magnetic nanoparticles (MNPs) is essential in the separation and detection of MNPs for applications such as magnetic biosensing. The sensitivity of magnetic biosensors inherently depends upon the distribution of captured MNPs within the sensing area. We previously demonstrated that the distribution of MNPs captured from evaporating droplets by ferromagnetic antidot nanostructures can be controlled via an external magnetic field.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 18200 Praha 8, Czechia.
The magnetic structures of the Ho-based i-MAX phase (MoHo)GaC were studied with neutron powder diffraction at low temperature. (MoHo)GaC crystallizes in the orthorhombic space group Cmcm. The material undergoes two successive antiferromagnetic transitions at T = 10 K and T = 7.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.
Unconventional spin-orbit torques arising from electric-field-generated spin currents in anisotropic materials have promising potential for spintronic applications, including for perpendicular magnetic switching in high-density memory applications. Here, all the independent elements of the spin torque conductivity tensor allowed by bulk crystal symmetries for the tetragonal conductor IrO are determined via measurements of conventional (in-plane) anti-damping torques for IrO thin films in the high-symmetry (001) and (100) orientations. It is then tested whether rotational transformations of this same tensor can predict both the conventional and unconventional anti-damping torques for IrO thin films in the lower-symmetry (101), (110), and (111) orientations, finding good agreement.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Physics, Mahasarakham University, Mahasarakham, 44150, Thailand.
Heat assisted magnetic recording (HAMR) technology is considered a solution to overcome the limitations of perpendicular magnetic recording and enable higher storage densities. To improve and understand the performance of magnetic writers in HAMR technology, it is crucial to possess a comprehensive understanding of both the magnetic field generated during the writing process and the thermal effects induced by the laser. In this work, we have developed a micromagnetic HAMR model with atomistic parameterization.
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