METHOD FOR MAKING AN ORDERED MAGNETIC ALLOY

• US 20140366990A1
• Filed: 10/25/2013
• Published: 12/18/2014
• Est. Priority Date: 06/17/2013
• Status: Active Grant

• Current Assignee: National Tsing Hua University
• Original Assignee: National Tsing Hua University
• Inventors: LAI, Chih-Huang, WANG, Liang-Wei, WU, Yun-Chung, SHIH, Wen-Chieh
• Granted Patent: US 9,767,836 B2
• Time in Patent Office: Days
• US Class Current: 148/121
• CPC Class Codes: C21D 1/26 Methods of annealing
• CPC Class Codes: C21D 2201/00 Treatment for obtaining particular effects
• CPC Class Codes: C21D 2251/02 Clad material
• CPC Class Codes: G11B 5/84 Processes or apparatus specially adapted for manufacturing record carriers
• CPC Class Codes: G11B 5/8404 manufacturing base layers
• CPC Class Codes: H01F 10/123 having a L10 crystallographic structure, e.g. [Co,Fe][Pt,Pd] thin films
• CPC Class Codes: H01F 10/30 characterised by the composition of the intermediate layers , e.g. seed, buffer, template, diffusion preventing, cap layers H01F10/06 and H01F10/32 take precedence
• CPC Class Codes: H01F 41/22 Heat treatment; Thermal decomposition; Chemical vapour deposition

Abstract

A method for making an ordered magnetic alloy includes (a) providing a thermally conductive base having opposite first and second surfaces; (b) forming a thermal barrier layer on the first surface of the thermally conductive base; (c) forming a disordered magnetic alloy layer on the thermal barrier layer, the disordered magnetic alloy layer being made from a disordered alloy which contains a first metal selected from Fe, Co, and Ni, and a second metal selected from Pt and Pd; and (d) after step (c), applying a transient heat to the thermally conductive base to cause rapid thermal expansion of the thermally conductive base, which, in turn, causes generation of an in-plane tensile stress in the disordered magnetic alloy layer.

Claims

1. A method for making an ordered magnetic alloy, comprising:

(a) providing a thermally conductive base having opposite first and second surfaces;

(b) forming a thermal barrier layer on the first surface of the thermally conductive base;

(c) forming a disordered magnetic alloy layer on the thermal barrier layer, the disordered magnetic alloy layer being made from a disordered alloy which contains a first metal selected from Fe, Co, and Ni, and a second metal selected from Pt and Pd; and

(d) after step (c), applying a transient heat to the thermally conductive base to cause rapid thermal expansion of the thermally conductive base, which, in turn, causes generation of an in-plane tensile stress in the disordered magnetic alloy layer to thereby order the disordered magnetic alloy layer.

2. The method of claim 1, wherein the application of the transient heat in step (d) is conducted by heating the thermally conductive base from an initial temperature to a phase-changing temperature T_a at a heating rate ranging from 20 to 50°

C./sec, such that 0.13T_m<

T_a<

0.35T_m, where T_m is the melting point of the disordered alloy.

3. The method of claim 2, wherein the application of the transient heat in step (d) is conducted by heating the second surface of the thermally conductive base with a light source having a wavelength ranging from 400 nm to 1100 nm.

4. The method of claim 3, wherein the thermally conductive base is made from Si, the thermal barrier layer being made from silica, the disordered magnetic alloy layer being ordered to form an ordered magnetic alloy layer having (001) preferred orientation.

5. The method of claim 3, wherein the thickness of the thermally conductive base ranges from 1.5 μ

m to 650 μ

m, and the thickness of the thermal barrier layer ranges from 10 nm to 400 nm.

6. The method of claim 5, wherein the first metal is Fe, and the second metal is Pt.

7. The method of claim 6, wherein the thickness of the thermally conductive base ranges from 1.5 μ

m to 450 μ

m, and the thickness of the thermal barrier layer ranges from 10 nm to 200 nm, and wherein 0.26T_m<

T_a≦

0.30 T_m.

8. The method of claim 6, wherein the disordered magnetic alloy layer further contains an oxide, the thickness of the thermally conductive base ranging from 450 μ

m to 650 μ

m, and wherein 0.18T_m<

T_a≦

0.20 T_m.

9. The method of claim 6, wherein the disordered magnetic alloy layer further contains an oxide, the thickness of the thermally conductive base ranging from 200 μ

m to 300 μ

m, and wherein 0.13T_m<

T_a≦

0.20 T_m.