Microscopic Structure and Magnetic Properties of Bi Added FeMn Alloy

Magnetic thin films of Mn-ferrite (MnFe
₂
O
₄
) have shown a large perpendicular magnetic anisotropy by the evaporation method. The evaporation substances are the (AαBß)
_100-x
C
_x
system, where A, B, and C represent the matrix elements of combination for Mn, Fe, and Bi, respectively. For (Mn
₂₅
Fe
₇₅
)
₉₇
Bi
₃
, column-shaped MnFe
₂
O
₄
grains deposited on a substrate have an anisotropy constant of 4.4 × 10
⁵
erg/cm
³
, 4πM
_s
of 1.6 × 10
³
G, and H
_c
of 540 Oe. The structure and magnetic properties of such evaporated films are closely related. It was recognized that in order to obtain magnetic thin films with perpendicular anisotropy, it is important to form a first Bi-phase layer with ≪102≫ orientation on the substrate.