Patent ID: 8257840

Claim:
A security functional thin film, the thin film comprising the following characteristics: 1) elemental composition of the thin film having the following formula enabling chemical element encoding: [Co x Fe (1-x) ] m [Zr y Hf (1-y) ] h [Nb z Ta (1-Z) ] b A a R r , where each subscript in the formula indicates atomic ratio, satisfying a numerical relationship of: total number of atoms m+h+b+r+a=100; and x=0-1, y=0-1, z=0-1, 96≧m≧75, 0<h≦20, 0<b≦20, 0<a≦12, 0<r≦4; A in the formula is one or more metallic elements selected from Mo, Ni, Ru, Pd, Pt, and Ti; and R is one or more rare-earth elements; 2) the thin film being an amorphous structure; 3) the thin film having soft magnetic characteristics, and having the following in-plane magnetic anisotropy characteristics detectable by machine-readable security detection: Large Barkhausen effect being present along in-plane preferred direction of magnetization, while the Large Barkhausen effect significantly attenuates, or no signal thereof can be detected, in a direction perpendicular to the in-plane preferred direction of magnetization; and 4) the thin film having a thickness of 20-300 nm.