Bubble automotion channels by laser annealing

Guided bubble automotion has been achieved without an external dc in-plane field by laser annealing channels along which confined columns of bubbles translate under pulsed bias field modulation. Small amplitude bias-field pulsations couple to some types of Bloch-line containing bubbles, producing bubble translations along the channel because local stray in-plane fields are sometimes produced by the laser annealing process. With larger pulsations (≳10 Oe) other modes of automotion are observed which do not require Bloch lines and local stray fields, but instead require the local magnetization gradients present at the edge of the laser annealed region. A mechanism proposed to explain these automotions orthogonal to the magnetization gradients involves the skewed deflection effect and its nonlinear dependence on bubble velocity.