Magneto optical disc, apparatus for reproducing the same and method of reproducing the same

Claim 1

A magneto optical disc, comprising: a record layer to which information is magnetically recorded in information pits so that the magnetization of each information pit is directed in either one of two directions perpendicular to a surface of the optical disc; a switch layer, having perpendicular magnetic anisotropy at room temperature that is lower than that at a reproduction temperature, said reproduction temperature being determined by an irradiation power of a reproducing light beam; and a reproduction layer on an opposite side of said switch layer from, said record layer to which the magnetization of the information pits is transferred by a switched connection force of said switch layer wherein said record layer, switch layer and reproduction layer satisfy the following: Hc1<Hini<Hc3 at room temperature; and Hw1>Hc1 and Hc3-Hw3>0 at the reproduction temperature where Hc1=coercive force of the reproduction layer; Hc3=coercive force of the record layer; Hw1=switched connection force applied to the reproduction layer from the switch layer; Hw3=switch connection force applied to the record layer from the switch layer; and Hini=initializing magnetic field applied to said optical disc whereby an initializing magnetic field applied to said optical disc initializes only said reproduction layer and not said record layer.