Micromagnetic simulation was employed to investigate the influence of microstructure parameters on the realization of high coercivity in nanocrystalline MnAl alloys, a promising alternative to rare-earth-based permanent magnets. The study focused on the effects of crystallite size (10–200 nm) and intergrain layer properties (non-ferromagnetic and soft-magnetic) on coercive force (Hc) and remanent magnetization (M_r/M_s). Simulations were performed using GPU-accelerated mumax3 software, with material parameters set to match MnAl (K_u1 = 1.5 MJ/m³, A_ex = 19.9 pJ/m, M_sat = 0.66 MA/m). Results revealed that the highest coercivity (μ₀H_c = 0.5 T) was achieved for crystallite sizes between 30–90 nm, consistent with experimental literature. The shape of the crystallites (cubic vs. cylindrical) showed negligible influence except for larger sizes (200 nm). For non-ferromagnetic interlayers, coercivity peaked at 0.52 T with a 7-nm thickness, attributed to the magnetic isolation of crystallites, while thicker layers with reduced H_c could be associated with changes in magnetic interaction between crystallites. In contrast, soft-magnetic interlayers (α-Fe) caused a monotonic decline in both H_c and M_r/M_s with increasing thickness. These findings provide critical insights for optimizing MnAl-based magnets, highlighting the importance of crystallite size control and interlayer engineering in achieving high coercivity.

  We analyze the influence of thermal gradient and cooling rate on writability in 4 Tbpsi shingled heat-assisted magnetic recording employing a stochastic calculation. We separate the bit error rate bER for each grain column in 2 bits of data and focus on the mean magnetization reversal number per unit time 𝑁_- for the medium in the recording direction during writing. We introduce the medium writing temperature 𝛥𝑇_med and time 𝜏_med, which are temperature and time ranges, respectively, where the 𝑁_- value is larger than 1 ns^-1. We also introduce the Curie temperature variation time 𝜏_Tc and the field end temperature 𝑇_end. The 𝜏_med and 𝜏_Tc values are functions of the cooling rate, which is the product of the thermal gradient and the linear velocity. In contrast, the 𝑇_end value is a function of the thermal gradient only. When the writing field is small, write-error and erasure-before-write are mainly dominant, and the bER value is determined by the 𝜏_med and 𝜏_Tc values, respectively. When the writing field is large, erasure-after-write is mainly dominant, and the bER value is determined by the 𝑇_end value in addition to the 𝜏_Tc value.

  Vertical domain wall motion memory, which uses magnetic pillars composed of artificial ferromagnets with diameters of several tens of nanometers, is gaining attention as a next-generation high-capacity memory solution. In this memory device, where domain walls move vertically, deletion and insertion errors can occur due to fluctuations in domain wall displacement, which are influenced by the write and drive currents. In this study, we construct a read/write (RW) channel model incorporating probabilistic domain wall motion memory with a 512-bit pillar structure and evaluate an error correction system using a Levenshtein code concatenated with a Reed–Solomon (RS) code. The results show that, in the scheme where each pillar is divided into prespecified blocks and Levenshtein coding is applied, the frame error rate performance improves as the number of blocks increases. Furthermore, it was found that the decoding can achieve the frame error rate (FER) less than 10^-3 when the standard deviation of domain wall displacement variation is reduced to 0.042 or lower.

  Electric vehicles face range limitations, and expanding battery capacity raises cost and environmental concerns. Dynamic wireless power transfer (DWPT) offers a solution by charging electric vehicles while driving, but conventional road materials reduce transmission efficiency. Magnetizable concrete, in which magnetic materials are used as concrete aggregates, was considered to improve the efficiency of power transmission for DWPT. The use of plate-like Mn–Zn ferrite powder (to increase permeability) and Fe–10Si–5Al powder made from a crushed dust core (to reduce eddy current loss) was examined to enhance the properties of magnetizable concrete. In addition, a mixture of magnetic powders with different particle sizes was used as an aggregate to increase the filling rate of the magnetic powders in the concrete. As a result, magnetizable concrete with the following properties was obtained: cement concrete using plate-like Mn–Zn ferrite powder showed a specific permeability of 73 and iron loss (85 kHz and 0.05 T) of 270 kW/m³; geopolymer concrete using Fe–10Si–5Al powder showed a specific permeability of 21 and iron loss of 300 kW/m³.

  To improve the magneto-optical properties of Nd_0.5Bi_2.5Fe₅O₁₂ (Bi2.5:NIG) thin films, a Bi₃Fe₅O₁₂ (BIG) underlayer was introduced. Bi2.5:NIG thin films with a thickness of 150 nm were prepared on Nd₂BiFe₄GaO₁₂(Bi1Ga1:NIG)/BIG layers prepared on glass substrates, and Bi2.5:NIG/BIG layers were prepared on Gd₃Ga₅O₁₂(GGG)(100) substrates, where all samples were prepared by using the metal-organic decomposition method. The Faraday rotation angle at around a wavelength of 520 nm significantly increased from 16.7°/μm to 31.5°/μm for Bi2.5:NIG/Bi1Ga1:NIG/BIG/glass and from 18.5°/μm to 27.8°/μm on Bi2.5:NIG/BIG/GGG. We consider the improvement in the Faraday rotation angles of these samples’ BIG underlayer to have enhanced the epitaxial growth of Bi2.5:NIG, resulting in an improved crystallinity and Faraday effect for the Bi2.5:NIG thin films.