Magnetic patterning of Co/Pt multilayers by Ga ⁺ ion irradiation

Patterns separated by approximately 55-nm-wide lines on Co/Pt multilayers have been fabricated using a focused ion beam with a 30-keV Ga ⁺ ion source. The ion irradiation allows the magnetic moment in the irradiated lines to rotate 45 deg to 90 deg toward the film plane. The in-plane magnetization component of the irradiated lines increases as the ion dose increases. The balance of incoming and outgoing flux at intersections is maintained in orthogonal patterns, while exceptions have been observed in hexagonal and triangular patterns. In all patterns, irradiated lines and adjacent unirradiated elements have no magnetic interaction.