Patent ID: 8089829

Claim:
A thermally assisted magnetic recording medium comprising: a substrate; and at least two magnetic recording layers arranged on or above the substrate, the magnetic recording layers including a first magnetic recording layer and a second magnetic recording layer, the magnetic recording layers being hard magnetic layers, and the magnetic recording layers each containing magnetic grains and a non-magnetic substance magnetically segregating the magnetic grains from one another at grain boundaries, wherein the first magnetic recording layer has a magnetic anisotropy energy K u1 , a volume of grains v 1 , and energy K u1 v 1 for maintaining its recording magnetization; wherein the second magnetic recording layer has a magnetic anisotropy energy K u2 , a volume of grains v 2 , and energy for maintaining its recording magnetization of K u2 v 2 ; and wherein the ratio K u1 v 1 /k B T of the energy K u1 v 1 to a thermal fluctuation energy k B T, wherein k B represents a Boltzmann constant and T represents an absolute temperature, and the ratio K u2 v 2 /k 3 T of the energy K u2 v 2 to the thermal fluctuation energy k B T satisfy the following conditions: the ratio K u1 v 1 /k B T is larger than the ratio K u2 v 2 /k B T at room temperature but the ratio K u1 v 1 /k B T is smaller than the ratio K u2 v 2 /k B T at temperatures around the Curie temperature of the first magnetic recording layer.