Abstract: Process for writing on a material, in which said material is irradiated by means of a beam of light ions, such as for example He+ ions, said beam of light ions having an energy of the order of or less than a hundred keV, wherein this material comprises a plurality of superposed thin-layers, at least one of said thin layers being magnetic and in that one or more regions having sizes of the order of 1 micrometer or less are irradiated, the irradiation dose being controlled so as to be a few 1016 ions/cm2 or less, the irradiation modifying the composition of atomic planes in the material at one or more interfaces between two layers of the latter.

Abstract: Process for writing on a material, in which said material is irradiated by means of a beam of light ions, such as for example He+ ions, said beam of light ions having an energy of the order of or less than a hundred keV, wherein this material comprises a plurality of superposed thin-layers, at least one of said thin layers being magnetic and in that one or more regions having sizes of the order of 1 micrometer or less are irradiated, the irradiation dose being controlled so as to be a few 1016 ions/cm2 or less, the irradiation modifying the composition of atomic planes in the material at one or more interfaces between two layers of the latter.

Abstract: The invention provides a method of treating a material to cause the material to evolve from one phase to a more ordered phase, the method comprising an operation of irradiating the material in which the irradiating particles are suitable, by their nature and by their energy, for inducing displacements of the atoms in the material towards positions that favor ordering of the material. Advantageously, the invention also provides apparatus for magnetically recording information, the apparatus comprising a material deposited on a substrate at a temperature of less than 350° C. and that has been subjected to irradiation with irradiating particles that are suitable, by their nature and their energy, for inducing displacements of the atoms in the material towards positions that favor relaxation of the material.