JP3417032B2 - Ferromagnetic resonance device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferromagnetic magnetic resonance apparatus, and more particularly to a ferromagnetic magnetic resonance apparatus which is a device mounted on a microwave communication tuner or the like.

[0002]

Conventionally, as a device using a ferromagnetic magnetic resonance, yttrium - garnet consisting of iron (. Hereinafter abbreviated as YI G) is the one used as the ferromagnetic magnetic resonance body are known. In such a device, by forming the ferromagnetic magnetic resonator in a spherical shape, the demagnetizing field coefficients in the longitudinal direction and the transverse direction become equal to each other, so that the saturation magnetization (4π M Since the term s) is deleted, the resonance frequency drift due to the temperature characteristic of the saturation magnetization does not occur in principle.

By the way, in recent years, there has been a demand for a device using ferromagnetic magnetic resonance that is low in price and excellent in mass productivity. In order to realize such a device, a so-called microstrip line is used. It is necessary to form a ferromagnetic magnetic resonance body integrated in a basic microwave integrated circuit (hereinafter abbreviated as MIC). As such a ferromagnetic magnetic resonance body, a ferromagnetic film formed in a thin film shape is used. A magnetic resonance element is used.

If the aspect ratio of the ferromagnetic magnetic resonance element is sufficiently large, its resonance frequency fr is given by the following equation.

Fr = γ (H ₀ −4π M s) (1)

In equation (1), γ, H ₀ , and 4π M
s is the gyromagnetic ratio, the externally applied magnetic field, and the saturation magnetization, respectively. As shown in the equation (1), the externally applied magnetic field H ₀
The resonance rises from when the saturation magnetization reaches 4π M s,
Subsequent fr is directly proportional to the magnitude of H ₀ .

In this case, however, unlike the above-mentioned spherical ferromagnetic magnetic resonance body which is three-dimensionally symmetrical in shape, in the above ferromagnetic magnetic resonance element, the drift of the resonance frequency fr due to the temperature characteristic of the saturation magnetization thereof. It is so large that it is not practical as it is.

Therefore, it has been proposed to provide a permanent magnet having the opposite characteristics in which the temperature characteristics of the saturation magnetization and the ferromagnetic magnetic resonance element are opposite to each other. That is, in the conventional ferromagnetic magnetic resonance apparatus, as shown in FIG. 2, a first magnetic core 101 formed in a substantially E shape and the first magnetic core 10 are formed.
1 and the respective core portions 101a, 101 at both ends of the E-shape
The second magnetic core 102 formed in a substantially rectangular shape butted at b, and the E-shaped central core portion 101 of the first magnetic core 101 for supplying a control current.
a magnetic coil 103 wound around c, a MIC 104 in which a ferromagnetic magnetic resonance body is integrated, a permanent magnet 105 having an inverse characteristic in which the saturation magnetization has temperature characteristics opposite to each other, and a uniform magnetic field distribution. And the pole piece 106 having a high magnetic permeability.

Here, the MIC 104 and the permanent magnet 10
5 and the pole piece 106 are formed to have substantially the same width, and are formed between the E-shaped central core portion 101c of the first magnetic core 101 and the second magnetic core 102. It is arranged in the gap 107.

That is, in the gap 107, MI
The C104 is arranged on the surface of the second magnetic core 102, which is one of the magnetic poles, by being bonded to the lower surface of the second magnetic core 102.
Reference numeral 5 denotes the core portion 101 which is the other magnetic pole at the upper surface portion thereof.
The pole piece 106 is joined to the lower end of the permanent magnet 105, and the pole piece 106 is joined to the lower surface of the permanent magnet 105. 108 is formed.

In this ferromagnetic magnetic resonance apparatus, a fixed magnetic field is generated by the permanent magnet 105 and the pole piece 106, and the magnetic field is controlled by adjusting the current flowing through the magnetic coil 103, so that the resonance can be tuned. It is regarded as a device. In this case, the resonance frequency drift due to the saturation magnetization of the ferromagnetic magnetic resonance element integrated in the MIC 104, which fluctuates with the ambient temperature of the ferromagnetic magnetic resonance apparatus, is offset and compensated by the inverse characteristic of the permanent magnet 105. Will be.

[0012] To examine the inhibitory effect of the drift of the resonance frequency due to the saturation magnetization of the above-described ferromagnetic magnetic resonance device, the saturation magnetization (4π M s) is a ferromagnetic MR element of the YI G of 0.085 (T) An experiment was conducted on the ambient temperature dependence of the resonance frequency drift in the case where the permanent magnet 105 was provided to perform the offset compensation by the inverse characteristic and the case where the permanent magnet 105 was not provided.

As a result, as shown in FIG. 3, it can be seen that the offset compensation clearly suppresses the drift of the resonance frequency as compared with the case where the permanent magnet 105 is not provided.

[0014]

As described above, by using the permanent magnet 105 to suppress the drift of the resonance frequency, the ferromagnetic magnetic resonance apparatus can be used as a local oscillator of a communication device or the like. , And can be sufficiently used for applications such as controlling with a phase lock loop (PLL) circuit.

However, in the conventional ferromagnetic magnetic resonance apparatus having the structure shown in FIG. 2, the magnetic coil 1 is used.
03 when a control current is applied to the magnetic coil 103
The temperature rise due to self-heating caused by the non-uniformity in the ferromagnetic magnetic resonance apparatus becomes
An initial drift of the resonance frequency occurs after the control current (tuning current) is applied to the device, and there is a problem when the device is used in an application requiring a high-speed response.

That is, when a control current is applied to the magnetic coil 103 and self-heating occurs in the magnetic coil 103 due to the control current, the heat conduction path of the heat is generated between the MIC 104 and the permanent magnet 105 in the ferromagnetic magnetic resonance apparatus. Since they are different from each other, a temperature difference occurs between the two, and a relatively large initial drift of the resonance frequency occurs before the two reach the thermal equilibrium state.

FIG. 4 shows a typical example of the initial drift of the resonance frequency. As shown in this characteristic diagram, the magnetic coil 10
Magnetic resonance is generated by passing a predetermined control current to 3, and the resonance frequency becomes fr1 at that moment, but when the ambient temperature becomes almost constant over time, the resonance frequency is always lower than the initial resonance frequency. It drifts, and the resonance frequency becomes almost constant at fr2 at a certain time t.

This is considered to be caused by the following. First, the self-heat generated from the magnetic coil 103 is generated by the E-shaped central core portion 1 of the first magnetic core 101.
01c, and further to the permanent magnet 105 joined to the end face of the core portion 101c, and after a while, this heat is transmitted to the MIC 104. As described above, there is a time lag in heat transfer between the permanent magnet 105 and the MIC 104, which causes a temperature difference between the two for a while.

Since the permanent magnet 105 compensates for the drift of the resonance frequency, the magnetizing force of the permanent magnet 105 is selected to have a negative characteristic with respect to the temperature rise.
It acts to weaken the control magnetic field generated by 3. On the other hand, in the ferromagnetic magnetic resonance element in the MIC 104, heat transfer is delayed as compared with the permanent magnet 105. Therefore, the effect of the permanent magnet 105 is predominant and the resonance frequency is lowered as a whole.
And become a thermal equilibrium state and the characteristics of both are balanced (time t, resonance frequency fr2), and the resonance frequency becomes a constant value.

Since it usually takes about 1 hour to reach the time t, and the resonance frequency is drastically lowered, the ferromagnetic magnetic resonance apparatus is used for applications requiring quick operation. This is extremely inconvenient in some cases.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress initial drift of the resonance frequency and provide a quick response when the resonance frequency is required to be changed. A ferromagnetic magnetic resonance device capable of compensating for the drift of the resonance frequency due to the temperature characteristic of the saturation magnetization of a ferromagnetic magnetic resonance element made of a thin film with a permanent magnet and providing sufficient practicality. To provide.

[0022]

According to the present invention, a first magnetic pole having a magnetic coil, a second magnetic pole arranged opposite to the first magnetic pole, and a ferromagnetic magnetic resonance element are integrated. A circuit, and a ferromagnetic magnetic resonance device having a permanent magnet having a temperature characteristic of magnetization opposite to that of the ferromagnetic magnetic resonance element, the integrated circuit and the permanent magnet being laminated,
The laminated integrated circuit and permanent magnet are arranged on one of the magnetic poles.

At this time, in order to make the magnetic field distribution uniform,
The integrated circuit and the permanent magnet may be laminated via a pole piece having a high magnetic permeability.

[0024]

In the ferromagnetic magnetic resonance apparatus according to the present invention,
An integrated circuit in which a ferromagnetic magnetic resonance element is integrated and a permanent magnet having an inverse characteristic that is opposite to that of the ferromagnetic magnetic resonance element are stacked, and the stacked integrated circuit and the permanent magnet are either magnetic poles. It is located above. Therefore, when a control current is applied to the magnetic coil, heat is generated in the ferromagnetic magnetic resonance device and the permanent magnet in the integrated circuit in the ferromagnetic magnetic resonance device when self-heating occurs in the magnetic coil due to the control current. At about the same time, heat conduction occurs and thermal equilibrium is reached immediately. Therefore, the initial drift of the resonance frequency generated until reaching the thermal equilibrium state due to the temperature difference between the two is suppressed to a negligible level. Therefore, when it becomes necessary to change the frequency to a predetermined value, even if the control current applied to the magnetic coil is changed, it is possible to rapidly resonate to the predetermined frequency with almost no initial drift. .

[0025]

Embodiments of the ferromagnetic magnetic resonance apparatus according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the ferromagnetic magnetic resonance apparatus according to this embodiment has a first magnetic pole 1 formed in a substantially E shape, the first magnetic pole 1 and its E shape. The second magnetic pole 2 is formed in a substantially rectangular shape, which is abutted by the core portions 1a and 1b at both ends, and the E-shaped central portion of the first magnetic pole 1 for supplying a control current. The magnetic coil 3 wound around the core portion 1c, the MIC 4 in which the ferromagnetic magnetic resonance body is integrated, the permanent magnet 5 having an inverse characteristic in which the temperature characteristics of the saturation magnetization are opposite to the MIC 4, and the magnetic field distribution And a pole piece 6 having a high magnetic permeability for homogenization.

Here, the MIC 4, the permanent magnet 5 and the pole piece 6 are formed so that their widths are substantially the same, and the E-shaped central core portion 1c and the second portion of the first magnetic pole 1 are formed. Is disposed in a gap 7 formed between the magnetic pole 2 and the magnetic pole 2.

That is, in the gap 7, the permanent magnet 5 is arranged on the surface of the second magnetic pole 2, which is one of the magnetic poles, by being joined to the lower surface of the second magnetic pole 2, and the pole piece 6 is provided on the upper surface thereof.
The MIC 4 is bonded and disposed on the lower surface of the MIC 4, and a gap 8 is formed between the upper surface of the MIC 4 and the core 1c.

In this ferromagnetic magnetic resonance apparatus, a fixed magnetic field is generated by the permanent magnet 5 and the pole piece 6, and the current flowing through the magnetic coil 3 is adjusted to control the magnetic field so that the resonance can be tuned. It is regarded as a device. In this case, the resonance frequency drift due to the saturation magnetization of the ferromagnetic magnetic resonance element integrated in the MIC 4 that fluctuates with changes in the ambient temperature of the ferromagnetic magnetic resonance apparatus is
The reverse characteristic of the permanent magnet 5 causes offset compensation.

Further, in the above-mentioned ferromagnetic magnetic resonance apparatus, as described above, the MIC 4 in which the ferromagnetic magnetic resonance elements are integrated and the permanent magnet 5 having an inverse characteristic opposite to that of the ferromagnetic magnetic resonance element are laminated. And this stacked MI
The C4 and the permanent magnet 5 are disposed on the second magnetic pole 2, which is one magnetic pole. Therefore, when a control current is applied to the magnetic coil 3, heat is generated in the magnetic coil 3 by the control current, heat is generated in the ferromagnetic magnetic resonance device and the permanent magnetic resonance element in the integrated circuit and the permanent magnet. Heat conduction occurs in the magnet 5 almost at the same time, and a thermal equilibrium state is reached immediately. Therefore, the initial drift of the resonance frequency generated until reaching the thermal equilibrium state due to the temperature difference between the two is suppressed to a negligible level. Therefore, when it becomes necessary to change the frequency to a predetermined value, even if the control current applied to the magnetic coil 3 is changed, it is possible to rapidly resonate to the predetermined frequency with almost no initial drift. Become.

As described above, in the ferromagnetic magnetic resonance apparatus according to the above-described embodiment, the resonance frequency drift due to the temperature characteristic of the saturation magnetization of the ferromagnetic magnetic resonance element formed of the thin film formed in the MIC 4 causes the resonance frequency drift. Even when self-heating is generated in the magnetic coil 3 by instantaneously changing the frequency when performing the offset compensation, the reduction in the resonance frequency that occurs is almost negligible. Therefore, for example, a tuner device such as a microwave communication device or a TV receiver that needs to be tuned to a frequency for a while and then quickly tuned and stabilized when changing to another tuning frequency. It becomes possible to cope with such a situation.

In the above embodiment, the MIC 4 and the permanent magnet 5 via the pole piece 6 are arranged on the side of the core portion 1c which is one magnetic pole, but they are the other magnetic pole. It may be arranged on the second magnetic pole side.

[0033]

According to the ferromagnetic magnetic resonance apparatus of the present invention, the first magnetic pole having the magnetic coil, the second magnetic pole forming each magnetic pole together with the first magnetic pole, and the ferromagnetic magnetic resonance element. Is provided, and a permanent magnet having a temperature characteristic of magnetization opposite to that of the ferromagnetic magnetic resonance element, the integrated circuit and the permanent magnet are laminated, and the laminated integrated circuit and the permanent magnet are Since it is arranged on one of the above magnetic poles, when the resonance frequency is required to be changed, the initial drift of the resonance frequency can be suppressed and a quick response is possible, and it is made of a thin film. It is possible to provide a system in which the drift of the resonance frequency due to the temperature characteristic of the saturation magnetization of the ferromagnetic magnetic resonance element is offset and compensated by the permanent magnet, and the system has sufficient practicality.

Further, according to the present invention, in order to make the magnetic field distribution uniform, the integrated circuit and the permanent magnet are laminated through a pole piece having a high magnetic permeability.
It is possible to provide a system in which the permanent magnet offsets and compensates for the drift of the resonance frequency due to the temperature characteristic of the saturation magnetization of the ferromagnetic magnetic resonance element made of a thin film, and can be given more sufficient practicality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing the configuration of a ferromagnetic magnetic resonance apparatus according to this example.

FIG. 2 is a sectional view schematically showing a configuration of a conventional ferromagnetic magnetic resonance apparatus.

FIG. 3 is a characteristic diagram showing an effect of suppressing temperature drift when a permanent magnet is used.

FIG. 4 is a characteristic diagram showing an initial drift of a resonance frequency due to self-heating of a magnetic coil.

[Explanation of symbols]

1st magnetic pole 2 second magnetic pole 3 magnetic coil 4 MIC 5 permanent magnets 6 pole pieces 8 voids

Claims (2)

(57) [Claims] 1. A first magnetic pole having a magnetic coil, a second magnetic pole arranged so as to face the first magnetic core, an integrated circuit in which a ferromagnetic magnetic resonance element is integrated, and a temperature of magnetization. A permanent magnet having characteristics opposite to those of the ferromagnetic magnetic resonance element is provided, and the integrated circuit and the permanent magnet are laminated, and the laminated integrated circuit and the permanent magnet are provided on one of the magnetic poles. A ferromagnetic magnetic resonance apparatus characterized by being arranged. 2. The ferromagnetic magnetic resonance apparatus according to claim 1, wherein the integrated circuit and the permanent magnet are laminated via a pole piece having a high magnetic permeability for making the magnetic field distribution uniform.