Grain Diameter and Coercivity of Fe, Ni, and Co Metals

“…The L ex value of Fe 16 N 2 was roughly deduced to be 4 nm if K u = 1 MJ m ¹3 and 14 nm if K u = 0.1 MJ m ¹3 using the exchange stiffness constant of Fe. 24) Figures 5(c, d) clearly indicate that D > L ex , so the smaller grain size led to the larger H c .…”

Section: ¡¤¤-Fe 16 Nmentioning

confidence: 87%

“…Such small grain sizes can also make the H c small, even if L1 0 -FeNi forms, because a reduction of D (grain size) increases H c if D > L ex (exchange length), but it decreases H c if D < L ex . 24) The L ex value of L1 0 -FeNi was roughly deduced to be 4 nm if K u = 1 MJ m ¹3 and 12 nm if K u = 0.1 MJ m ¹3 using the average exchange stiffness constants of Fe and Ni. 24) These L ex values are comparable to the actual D values.…”

Section: L1 0 -Fenimentioning

confidence: 99%

“…24) The L ex value of L1 0 -FeNi was roughly deduced to be 4 nm if K u = 1 MJ m ¹3 and 12 nm if K u = 0.1 MJ m ¹3 using the average exchange stiffness constants of Fe and Ni. 24) These L ex values are comparable to the actual D values. Thus, an increase in H c with temperature is due to an increase in grain size, as indicated by SEM images (Figs.…”

Section: L1 0 -Fenimentioning

confidence: 99%

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FeNi and Fe<sub>16</sub>N<sub>2</sub> Magnets Prepared Using Leaching

et al. 2019

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L1 0 -type FeNi alloys and ¡AA-Fe 16 N 2 are candidates for permanent magnets without precious metals, but they are difficult to prepare because atomic diffusion is extremely slow below the orderdisorder transition temperature of L1 0 -FeNi (320°C) and because ¡AA-Fe 16 N 2 is a metastable phase. Here, we report trials for preparing them using leaching, which is a method to obtain porous metals with a high surface area. We used such chemically active porous alloys as precursors for preparing L1 0 -FeNi using the driving force of atomic diffusion and for preparing ¡AA-Fe 16 N 2 using high reactivity with ammonia. No proofs for obtaining the L1 0 -FeNi phase were observed, likely due to an Al impurity of 10 mol% and/or too small of a grain size. An Fe 16 N 2 with ¡AA phase was obtained. Although the saturation magnetization was smaller than that of Fe, a large coercivity (up to 121 kA m ¹1 ) was obtained.

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“…It has been reported that the coercivity of sputtered Fe is roughly proportional to the sixth power of the grain diameter below 20 nm, and is proportional to the reciprocal of the grain diameter at larger vdues. 21 Detailed magnetic results will be presented in another report.…”

Section: Experimental Mcmwymmentioning

confidence: 99%

Structural Transition in Cu/Fe Multilayered Thin Films

1996

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Microstructural development of Fe and Cu in Cu/Fe multilayers of layer thickness 1.5–10 nm prepared on Si, Ge, and MgO substrates by ion beam sputtering has been studied using x-ray diffraction and cross-sectional transmission electron microscopy (TEM). High-angle x-ray results show an fcc Cu structure and a distorted bcc structure in the Fe layers at 5 nm-layer-thickness and smaller, and bcc Fe (110) and fcc Cu (111) peaks in the 10 nm-layer-thickness samples. Lowangle x-ray diffraction indicates that the layers in the samples grown on MgO substrates have a more uniform and smooth layered structure than the multilayers grown on Si and Ge substrates, which results from larger grains in the MgO substrate samples for the same layer thickness. Relationships among growth, microstructure, and interfaces with layer thickness are discussed.

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Grain Diameter and Coercivity of Fe, Ni, and Co Metals

Cited by 14 publications

References 10 publications

Magnetic Modulation: Atomic CN and Thermal Coupling

Magnetic Modulation: Atomic CN and Thermal Coupling

FeNi and Fe<sub>16</sub>N<sub>2</sub> Magnets Prepared Using Leaching

Structural Transition in Cu/Fe Multilayered Thin Films

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