Control of magnetic anisotropy and magnetic patterning of perpendicular Co∕Pt multilayers by laser irradiation

Abstract

We report an approach to altering the magnetic properties of ͑111͒ textured Co/ Pt multilayer films grown on sapphire ͑0001͒ substrates in a controlled way using single-pulse laser irradiation. The as-grown films reveal a strong perpendicular magnetic anisotropy induced by interfacial anisotropy. We show that laser irradiation can chemically mix the multilayer structure particularly at the interfaces, hence reducing the perpendicular magnetic anisotropy and coercivity in a controlled manner depending on laser fluence. As a result, perpendicular films can also be magnetically patterned into hard and soft magnetic regions using a regular two-dimensional lattice of polystyrene particles acting as an array of microlenses.

Heat diffusion in magnetic superlattices on glass substrates

“…For instance, temperature increases induced by laser beams can modify the equilibrium conditions and start a magnetization precession, switch it between different easy axis minima [6,7], or modify the magnetization hysteresis loops in applied fields [8]. Magnetic structures induced by laser beams [9,10,11,12,13], all-optical switching (AOS) in thin ferrimagnetic rare-earth and ferromagnetic superlattices [14,15], hybrid structures [16] and granular media [17,18] have been observed. Local ultrafast [8,19] as well as thermal models of AOS [20,21,22,23,24] have been proposed.…”

Anisotropic Imprint of Amorphization and Phase Separation in Manganite Thin Films via Laser Interference Irradiation

“…This technique is suitable to pattern elemental semiconductors and compounds whose crystal structures are retained in the fast laser heating/cooling process, but its application to complex multi‐element materials has not been explored. As a related approach, laser interference irradiation (LII) was used to fabricate periodic structures in metal‐based thin films and multilayers . The mechanism of patterning is quite straightforward: the laser beams causes annealing or chemical intermixing mostly in one‐dimensional areas of light intensity maxima as a result of interference .…”

“…As a related approach, laser interference irradiation (LII) was used to fabricate periodic structures in metal‐based thin films and multilayers . The mechanism of patterning is quite straightforward: the laser beams causes annealing or chemical intermixing mostly in one‐dimensional areas of light intensity maxima as a result of interference . However, so far few studies have exploited the LII technique in patterning multi‐element compounds such as perovskite‐structured transition‐metal oxides.…”

Irreversible modification of magnetic properties of Pt/Co/Pt ultrathin films by femtosecond laser pulses

“…For low energies of light pulses, the thermally induced changes of the magnetization and magnetic anisotropy are reversible and may trigger a magnetization precession, 14,15 while with higher light intensities, irreversible changes of the structure can be achieved. Employing few-nanosecond laser pulses, a decrease of the magnetic anisotropy in Pt/Co/Pt systems 16,17 was observed; on the contrary, for Au/Co/Au the possibility of creating the out-of-plane magnetization state with semi-continuous laser irradiation was demonstrated. 18 The reported effects of such laser-annealing were consistent with thermal annealing as discussed above.…”