Controllable state conversions for S=1 bubble domains

A method of converting a bubble domain from an initial state having no vertical Bloch lines therein to a final state having a pair of unwinding vertical Bloch lines therein, comprising the steps of:

• applying a first magnetic field in a direction substantially normal to the direction of magnetization of said bubble domain in its initial state of sufficient magnitude tending to destabilize the magnetic wall state of said initial state domain, and
• applying a second magnetic field along the direction of magnetization of said domain, said second field being spatially uniform and time varying and having sufficient magnitude and rate of change with time to generate two vertical Bloch lines in said initial state domain, to produce a domain having a single pair of unwinding vertical Bloch lines therein.

A method for converting a first unichiral domain having wall magnetization of a first sense to a second unichiral domain having wall magnetization of a second sense, comprising the steps of:

• applying a spatially uniform, time varying magnetic field to said first unichiral domain, said magnetic field having a magnitude and rate of change with time sufficient to generate a circular Bloch line in said first unichiral domain, and
• moving said circular Bloch line along the height of said first unichiral domain to change the sense of chirality of said first domain to that of said unichiral domain.

A method for converting a first magnetic bubble domain having a first wall magnetization state to a second magnetic bubble domain having a second wall magnetization state where said first and second states have the same winding number, and where said first magnetic domain is located in a bubble domain material characterized by the absence of a capping layer thereon, comprising the step of:

• applying a time varying, spatially uniform magnetic field in a direction along the magnetization direction of said first magnetic bubble domain, said magnetic field having a magnitude and time rate of change sufficient to change the Bloch line state of said first magnetic bubble domain to the bloch line state of said second magnetic bubble domain, where the dynamical radius of said domain substantially lags behind the quasistatic radius corresponding to the instantaneous magnitude of said magnetic field.

A method for controllably changing the Bloch line state of a magnetic bubble domain from a first Bloch line state to a selected second Bloch line state, said domain being located in a magnetic medium characterized by the absence thereon of a magnetic capping layer having in-plane magnetization, said state being changed without changing the winding number of said domain, comprising the step of

• applying a spatially uniform, time-varying magnetic field pulse to said domain,
• said pulse having a leading edge and a trailing edge, where the magnitude and rate of change of said leading edge are chosen to produce only said selected second Bloch line state in said domain when said field pulse is applied in a direction to change the size of said domain so that its dynamical radius substantially lags behind the quasistatic radius corresponding to the instantaneous magnitude of said magnetic field pulse.