Patent ID: 8277961
Filing Date: 2012-10-02
Classification: G11B

Abstract:
1. A magnetic recording medium for use in a magnetic recording device in which a process of writing a signal is conducted at a temperature higher than a temperature in a state retaining a signal, comprising: an underlayer, a magnetic recording layer, and a protective layer sequentially laminated on a nonmagnetic substrate; the magnetic recording layer having two magnetic layers and an exchange coupling control layer inserted between the magnetic layers, the two magnetic layers being magnetically coupled through the exchange coupling control layer, wherein a coupling energy of the two magnetic layers and the exchange coupling control layer in the process of writing a signal and a coupling energy of the two magnetic layers and the exchange coupling control layer in the state of retaining a signal are different from each other, and the coupling energy Jw in the process of writing a signal and the coupling energy Jr in the state of retaining a signal satisfy a relation 0<Jw<Jr, wherein the exchange coupling control layer contains a magnetic element and a saturation magnetization M wherein a crystalline magnetic anisotropy constant Ku of the exchange coupling control layer is at least 1.0×10