Planar magnetoresistance thin film probe for magnetic field alignment

In combination,

• a magnetic bubble domain structure including;
• a layer of material which is capable of forming and supporting magnetic bubble domains therein;
• a magnetizable device supported by said layer for selectively manipulating a magnetic bubble domain in said layer;
• and
• means for applying magnetic fields to said structure;
• said magnetic fields including,
• a bias magnetic field which is substantially orthogonal to said structure and is useful in forming magnetic bubble domains in said layer and which bias magnetic field may include an in-plane component which is in the plane of said device, and a propagating magnetic field which is substantially in the plane of said device and is useful in propagating magnetic bubble domains in said layer,
• the improvement comprising:
• means for detecting the in-plane component of said bias magnetic field including,
• a planar magnetoresistance effect probe for measuring the in-plane component of the bias magnetic field applied to said magnetic bubble domain structure,
• said probe formed on said layer and substantially coplanar with said device,
• said probe comprising at least one magnetic element,
• said magnetic element having dimensions such that the demagnetization field of said element is greater than the coercivity and anisotropy field thereof;
• means for supplying a constant current to said magnetic element;
• and
• means for producing an output voltage signal adapted for sensing and measuring the change in magnetoresistance in said magnetic element in response to a magnetic field which change in magnetoresistance is a function of the in-plane component of the bias magnetic field in the plane of said magnetic element and said magnetic bubble domain device such that any non-symmetry in the output signal is a measure of the in-plane bias component of the bias magnetic field.