Geometry dependence of the annealing effect on the magnetic properties of Fe₄₈Co₅₂nanowire arrays

Abstract

Highly ordered Fe48Co52 nanowire arrays with various interpore distances and diameters were fabricated by electrochemical deposition. The change of their magnetic properties after annealing has great dependences on the interpore distance and the wire diameter. The model of the prolate ellipsoid chain modified with the magnetostatic interaction is employed to explain this geometry dependence of the annealing effect. After annealing at 550 °C in H2 atmosphere, good hard magnetic properties (at room temperature, coercivity Hc = 3.89 kOe, squareness Mr/Ms = 0.954; at 78 K, Hc = 4.55 kOe, Mr/Ms = 0.954) were obtained in the arrays with a diameter of about 22 nm and an interpore distance of about 50 nm.

Magnetic and magnetization properties of electrodeposited fcc CoPt nanowire arrays

“…The values of H c and SQ are comparatively small for samples L1, L2, L3 and L4 with d ¼ 200 nm having interwire distance of 250 nm. This decrease in H c and SQ with increasing diameter is due to the decrease of shape anisotropy and an increase of the magnetostatic dipole interactions, because the interwire distance of these samples is not much larger than the wire diameter [19]. The overall anisotropic field (H k ) is mainly determined by following three contributions: (1) the shape anisotropy field (2pM s ), which will induce a magnetic easy axis parallel to the nanowire axis, (2) magnetostatic dipole interaction field among the wires, which will induce a magnetic easy axis perpendicular to the nanowire axis and (3) the magnetocrystalline anisotropy field (H ma ).…”

Electrochemical synthesis of magnetic nanowires with controlled geometry and magnetic anisotropy

“…Many groups (Zhan et al, 2002;Su et al, 2005) interpret the magnetization reversal mechanism in Fe-Co nanowires using a model based on "chains of spheres" (Jacobs and Bean, 1955), where each nanowire is considered to be a chain of single domain spheres with uniaxial magnetic anisotropy connected with each other by a single contact point, which make them magnetically isolated. The calculated coercivity of the nanowires using the chains of spheres model is in good agreement with the experimental results presented by the authors.…”

Hexagonal-Type Ising Nanowire with Core/Shell Structure Designed with Half-Integer Spins: Compensation Behaviors and Phase Diagrams in the Temperature and Interaction Planes

“…In particular, many researchers are interested on examining the magnetic phenomena of nanowires. In the experimental area, a variety of magnetic nanowires have been synthesized and their magnetic properties have been investigated, such as Fe-Co [40], Co-Pt [41], Ni [42], Ga 1−x Cu x N [43], Fe [44], Fe 3 O 4 [45], Co [46], Fe-Pt [47], Ni-Fe [48], and Co-Cu [49]. In theoretical area, the magnetic nanowires have been investigated within the various theoretical methods, such as MCS [50][51][52][53], EFT [10,[12][13][14][54][55][56][57][58][59][60][61], and MFA [62,63].…”