Method and system for determining at least one property of magnetic matter
A method for determining at least one property of magnetic matter includes: applying a magnetic field to magnetic matter; directing first light on the magnetic matter at a first set of incident angles; receiving a first set of signatures associated with the first light scattered from the magnetic matter; varying orientation of the magnetic matter with respect to the magnetic field; directing second light on the magnetic matter at a second set of incident angles; receiving a second set of signatures associated with the second light scattered from the magnetic matter; determining, by processing the first set and the second set of signatures according to a dispersion relation, at least one property of the magnetic matter.
1. A method, comprising:
applying a magnetic field onto magnetic matter;
directing first light onto the magnetic matter at a first set of incident angles;
receiving a first set of signatures associated with the first light scattered from the magnetic matter;
varying an orientation of the magnetic matter with respect to the magnetic field;
directing second light onto the magnetic matter at a second set of incident angles;
receiving a second set of signatures associated with the second light scattered from the magnetic matter;
mapping the first set of signatures and the second set of signatures to a first set of spin waves and a second set of spin waves, respectively; and
determining at least one property of the magnetic matter by fitting the first set of spin waves and the second set of spin waves to a dispersion relation.
2. The method of claim 1 , wherein the at least one property of the magnetic matter includes at least one of an exchange parameter, a saturation magnetization, and a thickness of a magnetic layer of the magnetic matter.
3. The method of claim 2 , wherein the magnetic matter is a thin magnetic film deposited on a non-ferromagnetic material.
4. The method of claim 1 , wherein said varying the orientation of the magnetic matter with respect to the magnetic field includes rotating the magnetic matter in a plane such that the first set of incident angles is equal to the second set of incident angles.
5. The method of claim 1 , wherein said varying the orientation of the magnetic matter with respect to the magnetic field includes rotating one or both of the first light and the second light by an angle in a plane such that the first set of incident angles is equal to the second set of incident angles.
6. The method of claim 1 , wherein the dispersion relation is defined by the equation:
f
(
k
,
H
,
ϕ
,
t
)
=
μ
0
μ
B
g
h
(
H
-
H
k
+
2
A
ex
μ
0
M
s
k
2
+
𝒩
M
s
(
1
-
e
-
kt
kt
)
)
(
H
+
2
A
ex
μ
0
M
s
k
2
+
𝒩
M
s
(
1
-
e
-
kt
kt
)
sin
2
ϕ
)
where f is a frequency of a spin wave, g is a spectroscopic splitting factor, H is a magnetic-field strength of the magnetic field, H k is an out-of-plane anisotropy, A ex is an exchange parameter, M s is a saturation magnetization, k is a wavenumber of the spin wave, is a demagnetization factor for ultrathin films, t is a thickness of a magnetic layer of the magnetic matter, and ϕ is an angle between a direction of the spin wave and a direction of the magnetic field.
7. The method of claim 6 , wherein the demagnetization factor is given by =1-0.2338/n, where n is a number of monolayers.
8. The method of claim 6 , wherein:
said applying comprises applying the magnetic field onto the magnetic matter such that the angle ϕ is zero; and
said varying comprises varying the orientation of the magnetic matter with respect to the magnetic field such that the angle ϕ is 90 degrees.
9. A system, comprising:
at least one processor; and
a memory communicatively coupled with the at least one processor and storing machine-readable instructions that, when executed by the at least one processor, control the system to:
apply a magnetic field onto magnetic matter;
direct first light onto the magnetic matter at a first set of incident angles;
receive a first set of signatures associated with the first light scattered from the magnetic matter;
vary an orientation of the magnetic matter with respect to the magnetic field;
direct second light onto the magnetic matter at a second set of incident angles;
receive a second set of signatures associated with the second light scattered from the magnetic matter;
map the first set of signatures and the second set of signatures to a first set of spin waves and a second set of spin waves, respectively; and
determine at least one property of the magnetic matter by fitting the first set of spin waves and the second set of spin waves to a dispersion relation.
10. The system of claim 9 , wherein the at least one property of the magnetic matter includes at least one of an exchange parameter, a saturation magnetization, and a thickness of a magnetic layer of the magnetic matter.
11. The system of claim 9 , wherein the machine-readable instructions that, when executed by the at least one processor, control the system to vary the orientation include machine-readable instructions that, when executed by the at least one processor, control the system to rotate a base platform supporting the magnetic matter in a plane such that the first set of incident angles is equal to the second set of incident angles.
12. The system of claim 9 , wherein:
the first light and the second light are the same light; and
the machine-readable instructions that, when executed by the at least one processor, control the system to vary the orientation include machine-readable instructions that, when executed by the at least one processor, control the system to rotate one or both of the first light and the second light by an angle in a plane such that the first set of incident angles is equal to the second set of incident angles.
13. The system of claim 9 , wherein the dispersion relation is defined by the equation:
f
(
k
,
H
,
ϕ
,
t
)
=
μ
0
μ
B
g
h
(
H
-
H
k
+
2
A
ex
μ
0
M
s
k
2
+
𝒩
M
s
(
1
-
e
-
kt
kt
)
)
(
H
+
2
A
ex
μ
0
M
s
k
2
+
𝒩
M
s
(
1
-
e
-
kt
kt
)
sin
2
ϕ
)
,
where f is a frequency of a spin wave, g is a spectroscopic splitting factor, H is a magnetic-field strength of the magnetic field, H k is an out-of-plane anisotropy, A ex is an exchange parameter, M s is a saturation magnetization, k is a wavenumber of the spin wave, is a demagnetization factor for ultrathin films, t is a thickness of a magnetic layer of the magnetic matter, and ϕ is an angle between a direction of the spin wave and a direction of the magnetic field.
14. The system of claim 13 , wherein the demagnetization factor is given by =1-0.2338/n, where n is a number of monolayers.
15. The system of claim 13 , wherein:
the machine-readable instructions that, when executed by the at least one processor, control the system to apply the magnetic field include machine-readable instructions that, when executed by the at least one processor, control the system to apply the magnetic field onto the magnetic matter such that the angle ϕ is zero; and
the machine-readable instructions that, when executed by the at least one processor, control the system to apply the magnetic field include machine-readable instructions that, when executed by the at least one processor, control the system to apply the magnetic field onto the magnetic matter such that the angle ϕ is 90 degrees.