Magneto-optical recording medium and system for use with short wavelength light
First Claim
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1. A magneto-optical medium comprising:
- a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;
a second magnetic layer overlying the first magnetic layer, having a thickness t2, where 1 nm≦
t2 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Nd and Pr, and including at least one transition metal element selected from a group consisting of Fe and Co; and
a third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co.
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Abstract
A magneto-optical medium is comprised of three layers. The first layer is made of a rare earth-transition metal amorphous film from one to twenty nanometers thick. The second layer is comprised of a rear earth-transition metal amorphous film or crystalline film and is one to twenty nanometers thick. The third layer is comprised of a rare earth-transition metal amorphous film and is not less than two nanometers thick. The resulting medium has a sufficiently large magneto-optical effect even at short wave lengths and is perpendicular magnetized film. A data storage system including the magneto-optical medium therein.
21 Citations
24 Claims
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1. A magneto-optical medium comprising:
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a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a second magnetic layer overlying the first magnetic layer, having a thickness t2, where 1 nm≦
t2 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Nd and Pr, and including at least one transition metal element selected from a group consisting of Fe and Co; anda third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co. - View Dependent Claims (2, 3, 4)
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5. A magneto-optical medium comprising:
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a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a second magnetic layer overlying the first magnetic layer, having a thickness t2 where 1 nm≦
t2 ≦
20 nm, comprising a crystalline film including at least one element selected from a group consisting of Fe and Co; anda third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co. - View Dependent Claims (6, 7, 8)
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9. A magneto-optical medium, comprising:
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a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a second magnetic layer overlying the first magnetic layer, having a thickness t2, where 1 nm≦
t2 ≦
20 nm, comprising a material represented by the formula (A1-a Ba)x (Fe1-b Cob)y Tz, where A is at least one element selected from a group consisting of Nd and Pr, B is at least one element selected from a group consisting of Tb, Dy and Gd, T is at least one element selected from a group of transition metals for improving anti-corrosion, where 0≦
a≦
0.9, 0≦
b≦
1, 0≦
x≦
40, 0≦
z≦
10, and x+y+z=100; anda third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co. - View Dependent Claims (10, 11, 12)
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13. An optical data storage system comprising:
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a radiation source for providing a first radiation beam; a magneto-optical medium comprising a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;
a second magnetic layer overlying the first magnetic layer, having a thickness t2, where 1 nm≦
t2 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Nd and Pr, and including at least one transition metal element selected from a group consisting of Fe and Co; and
a third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a radiation transmission means for directing the first radiation beam from the radiation source to the medium; and a radiation reception means for receiving a second radiation beam from the medium and generating a data signal responsive thereto. - View Dependent Claims (14, 15, 16)
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17. An optical data storage system comprising:
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a radiation source for providing a first radiation beam; a magneto-optical medium comprising a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;
a second magnetic layer overlying the first magnetic layer, having a thickness t2 where 1 nm≦
t2 ≦
20 nm, comprising a crystalline film including at least one element selected from a group consisting of Fe and Co; and
a third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a radiation transmission means for directing the first radiation beam from the radiation source to the medium; and a radiation reception means for receiving a second radiation beam from the medium and generating a data signal responsive thereto. - View Dependent Claims (18, 19, 20)
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21. An optical data storage system comprising:
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a radiation source for providing a first radiation beam; a magneto-optical medium comprising a first magnetic layer having a thickness t1, where 1 nm≦
t1 ≦
20 nm, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy, and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;
a second magnetic layer overlying the first magnetic layer, having a thickness t2, where 1 nm≦
t2 ≦
20 nm, comprising a material represented by the formula (A1-a Ba)x (Fe1-b Cob)y Tz, where A is at least one element selected from a group consisting of Nd and Pr, B is at least one element selected from a group consisting of Tb, Dy and Gd, T is at least one element selected from a group of transition metals for improving anti-corrosion, where 0≦
a≦
0.9, 0≦
b≦
1, 0≦
x≦
40, 0≦
z≦
10, and x+y+z=100; and
a third magnetic layer overlying the second magnetic layer, having a thickness t3, where 2 nm≦
t3, comprising a rare earth-transition metal amorphous film including at least one rare earth element selected from a group consisting of Tb, Dy and Gd, and including at least one transition metal element selected from a group consisting of Fe and Co;a radiation transmission means for directing the first radiation beam from the radiation source to the medium; and a radiation reception means for receiving a second radiation beam from the medium and generating a data signal responsive thereto. - View Dependent Claims (22, 23, 24)
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Specification