Magnetic recording medium including an annealed alloy particle layer and method of producing the same
View Patent ↗A method of producing a magnetic recording medium including the steps of preparing alloy particles capable of forming a CuAu type or Cu 3 Au type ferromagnetic order alloy phase, forming an alloy particle layer on a support using the alloy particles, oxidizing the alloy particles, and annealing the alloy particle layer in a magnetic field under a reducing atmosphere. Also disclosed is a magnetic recording medium produced by the method, that is, a magnetic recording medium including a magnetic layer which contains magnetic particles in a CuAu type or Cu 3 Au type ferromagnetic order alloy phase and which has a squareness ratio of 0.75 or higher.
1. A method of producing a magnetic recording medium, the method comprising the steps of:
preparing alloy particles capable of forming a CuAu type or Cu 3 Au type ferromagnetic order alloy phase;
forming an alloy particle layer on a support using the alloy particles;
oxidizing the alloy particles; and
annealing the alloy particle layer in a magnetic field under a reducing atmosphere.
2. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particles are prepared by a reducing method.
3. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particles are prepared by a reverse micellization method.
4. The method of producing a magnetic recording medium of claim 1 , wherein at least one third element selected from Sb, Pb, Bi, Cu, Ag, Zn, and In is added to the alloy particles.
5. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particles are oxidized at a temperature of 0 to 150° C.
6. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particles are oxidized at a temperature of 0 to 100° C.
7. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particles are oxidized at a temperature of 15 to 80° C.
8. The method of producing a magnetic recording medium of claim 1 , wherein a number of bonds between a base metal and oxygen is controlled to be 0.5 to 4 by the oxidation treatment.
9. The method of producing a magnetic recording medium of claim 1 , wherein a number of bonds between a base metal and oxygen is controlled to be 1 to 3 by the oxidation treatment.
10. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particle layer is annealed at a temperature of 150 to 500° C.
11. The method of producing a magnetic recording medium of claim 1 , wherein the alloy particle layer is annealed at a temperature of 300 to 450° C.
12. The method of producing a magnetic recording medium of claim 1 , wherein the magnetic field at the time of annealing treatment is 7.96 to 7,961 kA/m (100 to 100,000 Oe).
13. The method of producing a magnetic recording medium of claim 1 , wherein the magnetic field at the time of annealing treatment is 7.96 to 5,573 kA/m (100 to 70,000 Oe).
14. The method of producing a magnetic recording medium of claim 1 , wherein the magnetic field at the time of annealing treatment is 796.2 to 1,592.4 kA/m (10,000 to 20,000 Oe).
15. The method of producing a magnetic recording medium of claim 11 , wherein the magnetic field at the time of annealing treatment is 796.2 to 1,592.4 kA/m (10,000 to 20,000 Oe).