JPS62219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature-sensitive magnetic material used, for example, as a thermal switch element or magnetic shunt element. It is something.

Conventionally, Mn-Zn ferrite, which is an oxide magnetic material, has been used as a temperature-sensitive magnetic material.
The thermal conductivity is low, the response to changes in ambient temperature is slow, and the temperature change in the magnetic field near the Curie point, which is required for a thermal switch element, is gradual, so the temperature range for on-off operation as a thermal switch is low. The disadvantage was that it became too wide.

The present invention relates to a metallic magnetic material with high thermal conductivity and whose magnetic properties change sharply near the Curie point.

First, changes in the Curie point depending on the composition of the present invention will be explained.

Example 1 Ni40, Cu2.0, Si0.5, Mn0.5, Cr5~20wt, %
The remaining Fe was melted in vacuum, rolled to a thickness of 0.5 mm, and annealed at 1000°C in vacuum. Figure 1 shows the relationship between the Curie point and Cr content of these samples. As is clear from FIG. 1, a magnetic material whose Curie point can be changed over a wide temperature range was obtained, and it can be seen that the material of the present invention can be used as a thermal switch element over a wide temperature range. In the composition of the present invention, the Curie point changes even if the amounts of Ni, Mn, and Fe are changed, but the rate of change is smaller than when the amount of Cr is changed.

Next, the characteristics of the present invention material will be explained in comparison with conventional materials.

Example 2 Ni40.2, Cr10.0, Cu1.99, Si0.41,
0.48wt Mn and % balance Fe were melted in vacuum, rolled to a thickness of 1 mm, and annealed in vacuum at 1000°C. of this sample
Figure 2 shows the temperature change of magnetic flux density B ₁₀ at 10 Oe. Mn, a conventionally used oxide magnetic material
- Compared to Zn ferrite, the rate of change of B ₁₀ near the Curie point is significantly larger, and as a temperature-sensitive element, it has the property of being able to be turned on and off sharply depending on the ambient temperature.

Example 3 Ni39.5, Cr14.5, Cu2.05, Si0.40,
FIG. 3 shows the temperature characteristics of B ₁₀ of a sample treated with 0.45 wt Mn and % balance Fe in the same manner as in Example 2. As in Example 2, the change in B ₁₀ was steep, which is a desirable characteristic for a temperature sensing element.

As described above, the magnetic material according to the present invention is of great value as a temperature-sensitive element for, for example, a thermal switch or a magnetic shunt element that can perform sharp on-off operations within a narrow temperature range. Furthermore, the magnetic material according to the present invention is useful as a temperature compensating material for microwave devices. An example of application to a circulator is shown below.

Example 4 FIG. 4 is a cross-sectional view showing the schematic structure of a circulator to which the temperature-sensitive magnetic material of the present invention is applied, in which 8 is a case, 3 and 3a are ferrite magnets, and 5 is a garnet-type soft magnetic material, which acts as a conductor. Used in combination. 4 and 4a are soft iron plates attached to flatten the distribution of the magnetic field generated by the ferrite magnets 3 and 3a and applied to the garnet 5. As an example, the temperature-sensitive magnetic materials 6 and 7 of the present invention are attached to the periphery of the ferrite magnets 3 and 3a in the form of a headband, as shown in FIG. The magnetic flux density of ferrite magnets decreases linearly as the temperature increases. Therefore, the magnetic field applied to the garnet 5 changes greatly as the temperature rises, as shown by the curve in FIG. 5A.
As a garnet, 4πM _s = 700G of Gd-Ca-V
The temperature change of this saturation magnetization 4πM _s is as shown in Fig. 6, and the maximum point T _N
is approximately 20℃. It is thought that by making the magnetic field applied in this flat part temperature range of 4πM _s more flat than the curve in FIG. 4A, it is possible to realize a circulator with stable characteristics over a wide temperature range.
The curve in Figure 5 (b) shows Ni40 as the temperature-sensitive magnetic material.
It is made of Cu2.0, Si0.5, Mn0.5, Cr15wt% balance Fe and has a Kyrie point of 20°C, and is wound around a ferrite magnet in a 0.5mm thickness in the form of a headband. The temperature change in the magnetic field when the temperature-sensitive magnetic material was wound, as shown in Figure 5 (b), showed that the flatness was significantly improved compared to (a) when it was not wound. As a characteristic of the circulator, Isolation Loss was measured at various temperatures and was as shown in Figures 7 and 8. Figure 7 shows the case of only ferrite magnets, and A is 20
℃B is the measured value at 80℃C is -20℃.

Figure 8 shows the results when the above-mentioned magnetic material according to the present invention is wound, and A to C are the measurement results at the same temperature as in Figure 7, indicating a highly improved element with little change in temperature characteristics of isolation loss. It shows that. 4πM as the garnet used
If the maximum point T _N of _s differs, it is sufficient to use a temperature-sensitive magnetic material whose composition has a different Curie point accordingly, and the material of the present invention is therefore of great utility for temperature compensation of microwave elements.

Although it is possible to obtain a material having a wider range of Curie points by further changing the Cr content, this is not practical due to poor applicability. Further, even if the content of other elements exceeds the claimed range, it is not impossible to obtain a similar material, but it is not preferable because heat treatment becomes difficult.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the amount of Cr and the Curie point.
FIGS. 2 and 3 are diagrams showing the relationship between B ₁₀ and temperature. 1...Inventive material, 2...Mn-Zn ferrite. Figure 4 is a schematic diagram of an example circulator using the material of the present invention, Figure 5 is a diagram showing the temperature change of the magnetic field applied to the garnet, A is for the case of only ferrite magnets, and B is for the case of winding the material of the present invention. represents the case. Figure 6 shows the temperature characteristics of garnet at 4πM _s , and Figure 7 shows the temperature characteristics of a conventional circulator.
A diagram showing the frequency characteristics of Isolation Loss. FIG. 8 is a diagram showing the frequency characteristics of Isolation Loss when the material of the present invention is used. 3, 3a... ferrite magnet, 5... garnet,
6,7...Material of the present invention.

Claims (1)

[Claims] 1 Ni35~45, Cu1~5, Si0.2~1.0, Mn0.2~
1.0, Cr5~18wt%, balance Fe.