Low-loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin-orbit interactions. So far, the lack of low-damping, magnetostrictive ferrite films has hindered the development of power-efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl-ferrite thin films with an unusually low Gilbert damping parameter (<3 × 10 ), as well as strong magnetoelastic coupling evidenced by a giant strain-induced anisotropy field (≈1 T) and a sizable magnetostriction coefficient (≈10 ppm), are reported. This exceptional combination of low intrinsic damping and substantial magnetostriction arises from the cation chemistry of NiZnAl-ferrite. At the same time, the coherently strained film structure suppresses extrinsic damping, enables soft magnetic behavior, and generates large easy-plane magnetoelastic anisotropy. These findings provide a foundation for a new class of low-loss, magnetoelastic thin film materials that are promising for spin-mechanical devices.
In this letter we describe the ground-state magnetic structure of the highly anisotropic helimagnet Cr 1/3 NbS 2 in a magnetic field. A Heisenberg spin model with Dyzaloshinkii-Moriya interactions and magnetocrystalline anisotropy allows the ground state spin structure to be calculated for magnetic fields of arbitrary strength and direction. Comparison with magnetization measurements shows excellent agreement with the predicted spin structure.Controlling the electrical properties of materials by manipulating their magnetic structure has been one of the primary themes in the field of magnetism research and its applications. Major technological innovations have been based on these efforts, such as giant magnetoresistance in magnetic multilayers systems 1 and magnetic tunneling effects 2 . Recently, non-trivial spin textures, e.g. solitons 3 and skyrmions 4,5 , have received much attention in a similar context 3,6-10 . These objects are especially interesting because of the stability granted by their topology. A detailed understanding of such spin structures, in relation with their effect on electrical properties, is expected to shed light on developing spin-texture based applications 10 . With its layered noncentrosymmetric crystal structure, the helimagnet Cr 1/3 NbS 2 is well-suited for investigations of spin structure, especially toward controlling electrical properties 11,12 . In Cr 1/3 NbS 2 , Cr 3+ ions are intercalated between the hexagonal 2H-NbS 2 layers and magnetically order at T C = 133 K 11,12 . The crystal structure's lack of inversion symmetry, caused by Cr intercalation, results in a helical magnetic ground state oriented along the crystalline c-axis, with spins aligned ferromagnetically within the ab planes. Unlike other well known helimagnets with B20 crystal structure 4,5 , Cr 1/3 NbS 2 only breaks inversion symmetry along the caxis, making it ideal for studying spin-textures in magnetic thin films 13 , which also break inversion symmetry only along the single axis normal to the plane of film.The quasi 2-dimensional (2D) nature of these layered ferromagnetic planes, paired with strong magnetocrystalline anisotropy, allows a clear distinction between the magnetically hard axis (i.e. c-axis of the crystal) and the easy plane (ab-plane). The above qualities of Cr 1/3 NbS 2 greatly resemble those of planar magnetic
Understanding the role of spin-orbit coupling (SOC) has been crucial to controlling magnetic anisotropy in magnetic multilayer films [1][2][3][4]. It has been shown that electronic structure can be altered via interface SOC by varying the superlattice structure, resulting in spontaneous magnetization perpendicular or parallel to the plane [5,6]. In lieu of magnetic thin films, we study the similarly anisotropic helimagnet Cr 1/3 NbS2, where the spin polarization direction, controlled by the applied magnetic field, can modify the electronic structure. As a result, the direction of spin polarization can modulate the density of states, and in turn affect the in-plane electrical conductivity. In Cr 1/3 NbS2, we found an enhancement of in-plane conductivity when the spin polarization is out-of-plane, as compared to in-plane spin polarization. This is consistent with the increase of density of states near the Fermi energy at the same spin configuration, found from first principles calculations. We also observe unusual field dependence of the Hall signal in the same temperature range. This is unlikely to originate from the non-collinear spin texture, but rather further indicates strong dependence of electronic structure on spin orientation relative to the plane. PACS numbers:Despite the fact that its typical energy scale in 3d ferromagnetic metals is small compared to other relevant scales such as band widths, SOC mixes the nature of the spin and orbital components of the Bloch state in a nontrivial way and leads to a variety of electrical transport phenomena e.g. the anomalous Hall effect (AHE), anisotropic magnetoresistance (AMR), and the planar Hall effect. In addition, the recent work in non-collinear magnetically ordered states and the related topological Hall effect [7][8][9] not only has renewed the pivotal role of SOC through the Dzyaloshinskii-Moriya (DM) interaction [10][11][12], but also has presented a possibility to employ these findings for functional components in magnetic devices [13,14]. Non-collinear magnetic ordering is also suggested to possibly manifest spin-orbit coupling in a complex manner, through the DM interaction [12,15,16]. Consequently, the modification of electronic structure by spin-orbit coupling is expected to make in-plane electrical transport sensitive to the magnetization orientation relative to the plane.Cr 1/3 NbS 2 has a layered crystalline structure, in which 3d transition metal Cr atoms are intercalated in the hexagonal 2H-type NbS 2 matrix as trivalent ions and magnetically order at T C = 133 K. The ferromagnetic layers of Cr 3+ lie coplanar with the crystallographic abplanes and the magnetic helix propagates along the caxis with a long pitch of 48 nm, corresponding to 40 unit cells [17]. Its helimagnetic ordering is attributed to the DM interaction, which originates from a broken inversion symmetry shared by all members of space group P 6 3 22 [17][18][19].
We report three distinct regions within the A-phase in Fe-doped MnSi, based on the evolution of magnetoresistance and the Hall effect as a function of orientation of applied field. Fe impurities as pinning centers and crystalline anisotropy are found non-negligible only at the boundary of the A-phase. Electrical transport characteristics unique to the A-phase not only remain robust, but also indicate a freely rotating skyrmion lattice, decoupled from underlying crystal structure or impurity pinning.PACS numbers:
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.