Method And Apparatus For Evaluating A Magnetic Recording Medium

Abstract

A method of evaluating a magnetic recording medium using a magnetic head having a reproduction element is disclosed The method includes the steps of (a) recording a signal in a predetermined area of the magnetic recording medium; (b) determining a first value of a reproduction output by reproducing the predetermined area of the magnetic recording medium; (c) determining a second value of the reproduction output by emitting an energy line having a power of a predetermined value onto the predetermined area and reproducing the predetermined area with the reproduction element during or after the emission of the energy line; and (d) calculating a change in the reproduction output due to the emission of the energy line based on the first value and the second value of the reproduction output.

1 . A method of evaluating a magnetic recording medium using a magnetic head having a reproduction element, the method comprising the steps of:
 (a) recording a signal in a predetermined area of the magnetic recording medium;   (b) setting an exposure position to be exposed to an energy line at a predetermined position with respect to a magnetic sensing part position in a recording layer of the magnetic recording medium, the magnetic sensing part position opposing a magnetic sensing part of the reproduction element, emitting the energy line having a power of a predetermined value, and determining a reproduction output by reproducing the predetermined area of the recording layer in which the signal is recorded with the reproduction element during the emission of the energy line;   (c) changing the exposure position and repeating said steps (a) and (b); and   (d) determining a property of the magnetic recording medium based on a relationship between the reproduction outputs and the exposure positions.   
     
     
         2 . The method as claimed in  claim 1 , wherein:
 a plurality of values different from each other are set for the power of the energy line, and the reproduction output is determined for each of the values of the power by performing said steps (a), (b), and (c) with respect to each of the values of the power before said step (d), and   said step (d) determines the property of the magnetic recording medium based on a relationship among the reproduction outputs, the exposure positions, and the power of the energy line.   
     
     
         3 . The method as claimed in  claim 1 , wherein:
 said step (b) determines a change over time in the reproduction output, and   said step (d) determines the property of the magnetic recording medium based on a relationship between the changes over time in the reproduction outputs and the exposure positions.   
     
     
         4 . The method as claimed in  claim 1 , wherein the exposure position is set by displacing the predetermined position relative to the magnetic sensing part position.