JPS5846472B2 - Magnetic material with rectangular hysteresis curve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic material having a rectangular hysteresis curve, and in particular provides a storage core material that operates over a wide temperature range.

As is well known, a magnetic material exhibiting a rectangular hysteresis curve is used as an annular magnetic core as a memory element in electronic computers and the like.

By the way, the magnetic material used for this type of magnetic core must have a rectangular magnetic hysteresis curve from the viewpoint of low noise and low l noise, and must have a small core drive current and therefore have a low coercive force H.
6, good temperature characteristics, low cost, etc. are desired.

Li-Mn-Zn-based ferrite is known as a low-cost magnetic core material that has a low driving current and can be sintered in air.

Moreover, C in this Li-Mn-Zn ferrite
It is also known that the temperature characteristics are improved by adding o.

In order to understand the effect of adding Co to this L i -Mn -Z n-based ferrite, the amount of Co added was adjusted from O to 2.0 mo/L.
The characteristics of the magnetic cores made of the various materials varied within the range of 0.25% were measured using a pulse sequence as shown in FIG. 1, according to the conventional method for evaluating the characteristics of this type of magnetic core.

In Figure 1, f is the drive current value, Id is the disturbance current value, UV1 is the maximum value of the output voltage of the non-disturbing "1" signal, and UV
1 indicates the maximum value of the output voltage of the disturbance "1" signal, and DVo indicates the maximum value of the output voltage of the disturbance "O" signal.

Figure 2 is a graph showing the measurement results, where t is "no interference"
■”The peaking time of the signal output pulse, the time from the 10th point of the pulse rise to the maximum value, S/N is UV1/
DV.

I gave it to you. As is clear from FIG. 2, L i −Mn
-Z Adding Co to n-based ferrite increases the DVo, thereby deteriorating the squareness ratio and worsening the S/N.

In other words, Co, which is used to improve temperature characteristics, is actually less desirable in terms of squareness ratio and S/N.

In order to solve this problem, a material is known in which Ni is added to Li-Mn-Co-based ferrite to maintain a high squareness ratio.

Figure 3 shows the same measurement results as in Figure 2 when the amount of Co added to LiMn-Zn ferrite was constant at 1.2 mol, and Nl was added in various amounts in the range of 0 to 10 mol.
As the amount of Ni added increases, DV decreases and S/N increases, and from comparison with FIG. It can be seen that the deterioration of /N can be compensated for.

In fact, the conventionally known Li-Mn-Zn-Co-
For Ni-based ferrite, it is said that the amount of Ni added must be 4.5 mol or more.

By the way, this L i -Mn -Z n -Co -
Temperature characteristics of Ni-based ferrite (AI(/AT(mA,
'C)) was measured for various amounts of Co and Ni added, and the results shown in FIG. 4 were obtained.

As is clear from Figure 4, if 3 mol% or more of Ni is added, the temperature characteristics will exceed -1.0 mVC, and the meaning of the improvement in temperature characteristics caused by the addition of Co will be lost. Become.

In view of the above, the present invention provides L i -M n -Z n -
The present invention aims to improve Co-based ferrite, and to provide a low-cost, low-drive-current storage core material that maintains a good squareness ratio without losing the temperature characteristic improvement effect of Co addition.

The storage core material of the present invention contains 70 to 80 mol% of iron oxide, 20 mol% of lithium oxide, and 6 to 2 mol% of manganese oxide.
In addition to the ferrite constituents selected so that the total is 100 moles in 5 moles, zinc oxide 2 to 20 moles, cobalt oxide O to 1.7 moles (not including 0), and nickel oxide O to 3 moles. Vanadium oxide (V2O5) as a subcomponent to lithium, manganese, zinc, cobalt nickel ferrite added with rice cake (not containing O) O, o 1 to 0.0
3wt% and bismuth oxide (Bi203) 0.01~
At least one of them is added at 0.6 wt% (however, in the case of combined addition, the total amount is 0.01 to 0.7 wt%).

) is a magnetic material with a rectangular hysteresis curve.

Briefly, the magnetic material of the present invention is LiMn-Z
n -Co -N i The amount of Ni added in the ferrite is suppressed to a range of 3 mol% or less, and V2O5,0,01 to 0.
03wt% or Bi2O30.01~0.6wt%
By adding it, a magnetic core material with good squareness ratio and temperature characteristics can be provided.

The reason for setting the NiO content to 3 mol% or less is that, as mentioned above, if the NiO3 mol value is exceeded, the temperature characteristics deteriorate.

In addition, V2O5 was added at 0.01 to 0.03 wt%, B
0.01 to 0.6 wt% of i203.

V 505 + B i203 0.01-0.7wt
% is because outside this range, the S/N improvement effect of these additions is not observed.

The reason for limiting the amount of other components is that outside the above range, Bi2
This is because the effect of adding O3 and V2O5 is no longer recognized, causing a decrease in squareness ratio, an increase in coercive force H6, and deterioration of temperature characteristics.

The magnetic core material of the present invention is produced by pre-calcining the mixed powder adjusted to the above-mentioned composition range in the atmosphere at 700 to 900°C, pulverizing and mixing, and adding a binder (for example, hollyvinyl alcohol) to form the desired shape. After pressure molding, it is heated to 1050'C to 12°C in an air atmosphere (or oxygen atmosphere).
The main firing is carried out at 00°C and then cooled in the same atmosphere.

FIG. 5 is a graph showing the characteristics of one embodiment of the present invention.
120313.5 mol%, Mn0 15.0 mol%, Z
n010.0 mol article, Fe 20371.5 mol%,
The characteristics obtained when various amounts of Bi2O3 were added to 1.5 mol% of Co and 1.0 mol% of Ni are shown.

As is clear from this figure, Bi2O3 is 0.01~Q
, when added in the range of 6 wt%, the coercive force Hc
B 1203 reaches its maximum when Q and 1 wt rise, and the temperature characteristics do not depend on the amount of Bi2O3 added and show a good value of constant -0.35 mA/°C.

It is also clear that both S/N and j-noise are improved.

FIG. 6 shows the data of the example when V2O5 is added, L + 20313°5 mol%, Mn015.0
V20 when V2O5 is added to 1.5 mol% of Co and 1.0 mol of Ni to 1.5 mol of Zn010.0 mol. The relationship between the amount of addition and characteristics is shown.

As is clear from this figure, VO is 0.01=0.03
By adding V2O5 in the wt% range of 5, Ho reaches its maximum at 0.05wt% of V2O5, and the temperature characteristics do not depend on the amount of V2O5 added and become -0.
, a constant value of 35 mA/'C.

It is also clear that both S/N and A noise are improved.

Figure 7 shows an example in which B 1203 and ■205 are jointly added, Li20313.5 mol%, MnO15.0
Mol%, Zn010.0mol%, Fe 20s 71
．． This is a diagram showing the characteristics when B l 20s and ■ 205 are jointly added to 5 mol %, Co 1.5 mol width and Ni 1.0 mol width.
For joint addition of 2O3 and ■205, 0.01 to 0.07
In the range of wt%, Ho has a maximum of ■■2O when Bi2O3 is 0.1wt%, and the curve becomes broader as the constant addition amount increases to 0.3wt%.

The temperature characteristics do not depend on the amount added and show a good value of -3.5 mA/'C.

It can also be seen that the S/N and d noise are improved.

As is clear from the above examples, the temperature characteristics of Li-Mn-Zn ferrites in which Co was added to improve the temperature characteristics and Ni was further added to improve the squaring deterioration From the viewpoint of deterioration of B1□03 to v20. This can be supplemented by the addition of , and therefore a magnetic core material with good temperature characteristics and good S/N, and therefore squareness ratio, can be obtained.

It goes like this t 203 and ■20. By the addition of
The reason why the characteristics are improved is that L i −Mn −Z n
-Bi2O3 and ■2 added to Co-Ni ferrite
This is thought to be due to the fact that 05 acts to smoothly promote the production reaction during ferrite production, form a dense spinel type ferrite, and make the crystal grains uniform.

As described above, according to the present invention, it is possible to obtain a magnetic core material that has good temperature characteristics, squareness ratio, and coercive force, and therefore has good S/N, 1 noise, and drive current.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a pulse sequence used for measuring magnetic core characteristics.
d...Disturbance current value, UV1...Maximum output voltage of non-disturbing "'1" signal, D■1... Maximum output voltage of disturbance "1" signal Value, DVo...
The maximum value of the output voltage of the disturbance "0" signal is shown.
Figure 3 shows the change in characteristics due to the addition of L i -M
n-Z n-C. Figure 4 is a diagram showing changes in characteristics due to the addition of Ni to ferrite, and Figures 5 to 7 are diagrams showing changes in temperature characteristics when Co and Ni are added to Li-Mn-Zn ferrite at the same time. is a diagram showing the characteristics of the embodiment of the present invention, and FIG.
FIG. 6 is a diagram showing changes in characteristics depending on the amount of i203 added, FIG. 6 is a diagram showing changes in characteristics depending on the amount of v205 added, and FIG. 7 is a diagram showing changes in characteristics due to addition of B I 20 +■205.

Claims (1)

[Claims] 1. Iron oxide (Fe203) 70-80 mo/L/%
, 7 to 20 moles of lithium oxide (L l 20 ),
2 to 20 moles of zinc oxide (ZnO) and 2 to 20 moles of zinc oxide (ZnO) and cobalt oxide (C
od) 0 to 1.7 mol% (excluding 0) and nickel oxide (Nip) O to 3 mol'% (excluding O) to lithium-manganese-zinc-cobalt-nickel ferrite, and Vanadium oxide (v2o5) as a component
0.01-0.03wt%a and bismuth oxide (Bt
203) Add at least 0.01~0.6vvt% (however, in case of combined addition, the total amount is 0.01~0,7w)
It is assumed to be t%. ) A magnetic material having a rectangular hysteresis curve.