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Abstract The vast high entropy alloy (HEA) composition space is promising for discovery of new material phases with unique properties. This study explores the potential to achieve rare‐earth‐free high magnetic anisotropy materials in single‐phase HEA thin films. Thin films of FeCoNiMnCu sputtered on thermally oxidized Si/SiO₂substrates at room temperature are magnetically soft, with a coercivity on the order of 10 Oe. After post‐deposition rapid thermal annealing (RTA), the films exhibit a single face‐centered‐cubic phase, with an almost 40‐fold increase in coercivity. Inclusion of 50 at.% Pt in the film leads to ordering of a singleL1₀high entropy intermetallic phase after RTA, along with high magnetic anisotropy and 3 orders of magnitude coercivity increase. These results demonstrate a promising HEA approach to achieve high magnetic anisotropy materials using RTA. 

We report the polarization-dependent Raman spectra of exfoliated MoI3, a van der Waals material with a “true one-dimensional” crystal structure that can be exfoliated to individual atomic chains. The temperature evolution of several Raman features reveals an anomalous behavior suggesting a phase transition of magnetic origin. Theoretical considerations indicate that MoI3 is an easy-plane antiferromagnet with alternating spins along the dimerized chains and with inter-chain helical spin ordering. The calculated frequencies of phonons and magnons are consistent with the interpretation of the experimental Raman data. The obtained results shed light on the specifics of the phononic and magnonic states in MoI3 and provide a strong motivation for further study of this unique material with potential for future spintronic applications. 

Abstract We report the results of polarization‐dependent Raman spectroscopy of phonon states in single‐crystalline quasi‐one‐dimensional NbTe₄and TaTe₄van der Waals materials. The measurements were conducted in the wide temperature range from 80 to 560 K. Our results show that although both materials have identical crystal structures and symmetries, there is a drastic difference in the intensity of their Raman spectra. While TaTe₄exhibits well‐defined peaks through the examined wavenumber and temperature ranges, NbTe₄reveals extremely weak Raman signatures. The measured spectral positions of the phonon peaks agree with the phonon band structure calculated using the density‐functional theory. We offer possible reasons for the intensity differences between the two van der Waals materials. Our results provide insights into the phonon properties of NbTe₄and TaTe₄van der Waals materials and indicate the potential of Raman spectroscopy for studying charge‐density‐wave quantum condensate phases. 

Abstract Topological insulators (TI) and magnetic topological insulators (MTI) can apply highly efficient spin‐orbit torque (SOT) and manipulate the magnetization with their unique topological surface states (TSS) with ultrahigh efficiency. Here, efficient SOT switching of a hard MTI, V‐doped (Bi,Sb)₂Te₃(VBST), with a large coercive field that can prevent the influence of an external magnetic field, is demonstrated. A giant switched anomalous Hall resistance of 9.2 kΩ is realized, among the largest of all SOT systems, which makes the Hall channel a good readout and eliminates the need to fabricate complicated magnetic tunnel junction (MTJ) structures. The SOT switching current density can be reduced to 2.8 × 10⁵ A cm⁻², indicating its high efficiency. Moreover, as the Fermi level is moved away from the Dirac point by both gate and composition tuning, VBST exhibits a transition from edge‐state‐mediated to surface‐state‐mediated transport, thus enhancing the SOT effective field to (1.56 ± 0.12) × 10⁻⁶ T A⁻¹ cm²and the interfacial charge‐to‐spin conversion efficiency to 3.9 ± 0.3 nm⁻¹. The findings establish VBST as an extraordinary candidate for energy‐efficient magnetic memory devices.