Intialization of magnetic features

Abstract

The embodiments disclose an alternating current (AC) erase process configured to cancel out existing polarity of stack magnetic features on both sides of the stack and an AC reset process configured to initialize the polarity of the device stack magnetic features of both sides of a stack configured to create a uniform polarity.

What is claimed is: 
     
         1 . A method comprising:
 applying a first magnetic field, using a first magnet, to magnetic features on both sides of a stack, wherein applying the first magnetic field erases magnetic polarity on both sides of the stack; and   applying a second magnetic field, using a second magnet, to polarize the magnetic features on both sides of the stack to create a uniform polarity in a same direction.   using an AC reset   
     
     
         2 . The method of  claim 1 , wherein the first magnet applying the first magnetic field applies an alternative current (AC) to cancel out existing polarities on both sides of the stack. 
     
     
         3 . The method of  claim 1  further comprising replacing the first magnet with the second magnet after applying the first magnetic field. 
     
     
         4 . The method of  claim 1 , wherein the applying the second magnetic field polarizes the magnetic features on both sides of the stack simultaneously. 
     
     
         5 . The method of  claim 1 , wherein applying the first magnetic field lowers total energy of the stack including a disc or magnetization back to a zero point. 
     
     
         6 . The method of  claim 1 , wherein the first magnetic field lowers energy state by eliminating all signals. 
     
     
         7 . The method of  claim 1 , wherein the stack comprises a bit patterned media, perpendicular, or other magnetic recording formats. 
     
     
         8 . The method of  claim 1  further comprising testing polarity of centers of the stack magnetic features using a head magnet. 
     
     
         9 . The method of  claim 8 , wherein the testing of the polarity of the centers of the stack magnetic features includes checking each magnetic feature center. 
     
     
         10 . The method of  claim 8 , wherein testing the polarity of the centers of the stack magnetic features includes checking a sampling of the magnetic features including bit patterned media features. 
     
     
         11 . A method comprising:
 transitioning a polarity of a plurality of magnetic features from a current polarity to a non-magnetic polarity using an alternating current (AC); and   initializing the polarity of the plurality of magnetic features from the non-magnetic polarity to a uniform polarity in a single pass by applying a magnetic field that is configured to magnetize the plurality of magnetic features in a same direction.   
     
     
         12 . The method of  claim 11 , wherein the plurality of magnetic features is in a magnetic layer on a first and second side of a substrate. 
     
     
         13 . The method of  claim 12 , wherein a south pole of magnetic features of the plurality of magnetic features on the first side of the substrate and a north pole of magnetic features of the plurality of magnetic features on the second side of the substrate are directed toward the substrate. 
     
     
         14 . The method of  claim 11 , wherein the transitioning comprises applying an alternating current (AC) erase process that is configured to set a magnetization of the plurality of magnetic features to a zero point. 
     
     
         15 . The method of  claim 11 , wherein the transitioning from the current polarity to the non-magnetic polarity is through application of another magnetic field using a transitioning magnet, and wherein the initializing the polarity from the non-magnetic polarity to the uniform polarity is through application of the magnetic field using an initializing magnet. 
     
     
         16 . The method of  claim 11  further comprising transitioning the polarity of the plurality of magnetic features to a non-magnetic phase. 
     
     
         17 . A method comprising:
 canceling a polarity of a plurality of magnetic features of a magnetic layer on a first and second sides of a substrate by applying a first magnetic field to the substrate, wherein the canceling initializes the polarity of the plurality of magnetic features to a no polarity charge; and   magnetizing the plurality of magnetic features from the no polarity charge to a polarity charge in a same direction, wherein magnetic features of the plurality of magnetic features on the first side has the same polarity as magnetic features of the plurality of magnetic features on the second side.   
     
     
         18 . The method of  claim 17 , wherein the magnetizing causes a substantially uniform polarization of the plurality of magnetic features. 
     
     
         19 . The method of  claim 17 , wherein the magnetizing comprises performing a single pass with a magnet. 
     
     
         20 . The method of  claim 17 , wherein the canceling transitions the plurality of magnetic features to a low energy state in the plurality of magnetic features on the first and second sides of substrate substantially simultaneously. 
     
     
         21 . The method of  claim 17 , wherein the plurality of magnetic features has a substantially random polarization prior to the canceling.