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Femtosecond laser-interference induced amorphization (FLIA) is used for forming a spatially periodic magnetic structure by selectively amorphizing the surface of bulk [Co.sub.2]MnSi. The periodicity of the modulated structure is decreased or the process can be modified to write two-dimensional pattern so that the resulting magnetic structure can be used for a permanent magnetic identification.

A magnetic grating with a periodicity of 2 μm was generated by selective crystallization of an amorphous Cu2MnSn thin film using femtosecond laser pulses. By irradiating the amorphous Cu2MnSn thin film with two-beam interference pattern of femtosecond laser pulses, alternating bands of ferromagnetic and paramagnetic phases were produced. The crystallized region was composed of ferromagnetic Cu2MnSn grains, whereas the amorphous region remained paramagnetic. Because crystallized Cu2MnSn is the only ferromagnetic phase that can be produced by heat-treatment of the amorphous Cu2MnSn thin film, a magnetic grating with high definition was produced. Moreover, the periodicity of the modulated structure can be reduced down to a submicrometer scale and extended to two dimensions so that the technique could be potentially utilized for magnetic patterning. [ABSTRACT FROM AUTHOR]

Femtosecond laser-interference induced amorphization (FLIA) was used to form a spatially periodic magnetic structure by selectively amorphizing the surface of bulk Co2MnSi. Regularly spaced alternating lines with a periodicity of 2 μm were produced by FLIA. Magnetic force microscopy of the samples clearly revealed one-dimensional periodic magnetic domains resulting from the modulated surface structure which was confirmed by transmission electron microscopy. The periodicity of the modulated structure can be further decreased or the process can be modified to write two-dimensional pattern so that the resulting magnetic structure can be potentially utilized for a permanent magnetic identification. [ABSTRACT FROM AUTHOR]