DE1764483B1 - Arrangement of several stacked, thin, ferromagnetic films of uniaxial anisotropy - Google Patents

Description

35 in which β is the maximum dispersion occurring in the films and 7 is an angular deviation resulting from the fabrication technique. The angles of the easy directions of adjacent magnetic layers with respect to the easy axis of the entire cell of an alternating field (40) and the magnetization 40 are approximately the same, but have opposite vectors (M ₁ , M ₂ ) at an angle of −45 °. The non-magnetic intermediate layer should be rotatable around a middle, easy axis (Ma ) running perpendicular to the direction of the alternating field between two adjacent magnetic layers (40) (made of about 80% nickel and 20% iron). Have thickness that an exchange coupling between

4. Arrangement according to claim 1, characterized 45 see the two adjacent nickel-iron layers characterized in that the Vormagnetisierungsrich- is practically insignificant.

of the neighboring films (14a and 16a etc.) This cell is in the so-called orthogonal field

form an angle of 180 ° with each other and operate a control method in which a first saturation field strength extending radially from the center of an opening extending through all films (14a external magnetic field, the amplitude of which is greater than that and 16a, etc.) causes the magnetization of all go through which is traversed by at least one winding (72) magnetic layers in the same direction in the hard, and that over the winding (72) direction, i.e. perpendicular to the externally in Erscheider arrangement (70) an alternating field (± H) occurs , easy direction of the entire cell can be shaped by which the magnetization vectors are rotated and the cell is thus magnetically saturated in this hard direction (M ₁ , M ₂ ) at an angle of ± 45 ° with respect to 55 (axis). In this process of turning the bias directions back and forth, an output device will be able to be electrified. tric voltage induces the change in

5. Arrangement according to claim 1, characterized in that the magnetization component in the easy direction is that the stacked one on top of the other is proportional to the cell. The magnetization of all films as self-contained bands (84a, 86a, 60 layers can be brought back to their starting position 84b, 86b) in the shape of a hollow cylinder, that a second, outer one, that the bias directions of the magnetic field, its direction to which the first vertical adjacent film is at an angle of 180 ° right, at least just then the entire cell is impressed with one another and of 90 ° with the circumferential direction when the first field subsides. In the case of the hollow cylinder and that the opening of this process, the magnetization vectors of the hollow cylinder are traversed by at least one winding (82) of all magnetic layers of the cell in the same direction, over which the arrangement (80) has an alternating field (80) along its easy axis. ± H) can be imprinted, from which the or brought back into the position rotated by 180 °.

large demagnetizing field, which is the magnetization vector forces to rotate within the thin layer. The precession cone of the magnetization vector is thereby extremely flat, so that 5 one has to consider its movement approximately as pure rotation within a single plane.

Because of the small thickness of the individual required for the coherent rotary switching process Film of a few thousand angstrom units

Since in this mode of operation of the known cell the magnetization vectors of all magnetic layers from the relevant external field in the same direction, i.e. from its easy axis into the hard axis z. B. in Clockwise and counterclockwise from the hard axis to its easy axis the electrical signal induced in the winding associated with the cell is a superimposed signal of that of induced separately for each magnetic layer

electrical signals, provided that the output of the magnetic energy that can be absorbed in the film is very high

Exchange coupling between the neighboring magnetic low values is limited. Accordingly is also

table layers is practically insignificant. If the electrical energy that the individual film converts

Insufficient thickness of the non-magnetic layers or between an input and output circuit

and is able to transmit a mutual magnetic influence to very small values limited between the broad sides of adjacent magnetic 15.

Layers takes place, the magnetization is known from British patent specification 872 070 vectors not within their associated layer - through an outer switching field, the strength of which is a geplane rotated, but point out from this level, know the process of exceeding the threshold thereby causing the single-layer structure, also mono-range rotary switching, which is yes called structure, in the neighboring shifts due to shorter switching times compared to switching gets lost. The rotational movement of the magnetization is characterized by a wall movement. To this one motion vectors within a level and those with this threshold value, below which the slower switching Movement linked, known, beneficial egg takes place through the wall movement, reduce properties can with the destruction of the mono and thus with weaker driving fields the robe area structure, what to achieve as "breaking the as tation switch is a special manufacturing domain" is no longer a maintenance process for a film with this property can be obtained. explained, in which the mentioned threshold value can even be set in the desired manner. To the work "by K. Steinbuch, Berlin / Göttingen / Explanation of the Heidelberg, 1962, pp. 276 to 178, shows that 30 processes become a stack of twenty as a model of thought in the case of flux reversal within a thin, ferro-unsupported film, each 100 Å thick Layer of uniaxial anisotropy three drawn, whose easy axes of magnetization are Processes, namely the wall movement, which is incoherent in terms of their orientation to one another Rotary switching and coherent rotary cutting. As a result of these differences, the mean switch, observed. The velocity of the flux 35 anisotropy energy of the stack decreased, to the reversal through the wall movement, also known as »wall ver- the threshold value in a linear relationship Called “shift”, but is of the order of magnitude.

of microseconds and is therefore with that of a reduction in the mean anisotropy ferrites comparable. The incoherent rotational energy of the stack compared to the full anisotropy switching is mainly observed when the 40 energy of each individual film means practically one outer switching field almost the same direction as the transition to isotropy, in which in inevitable uniaxial anisotropy, i.e. the slight magnetization link for the extremely short switching times axis of the thin, ferromagnetic layer has. necessary coherence of rotary shifting lost-if this second process in which switching times must go into. There is no difference between the of the order of magnitude between 10 and 100 nsec measured 45 coherent and incoherent rotary switching im be switched off, the Rieh may getung in contrast to the other prior publications of the outer panel is not even close to making, it must be assumed that with regard to the orientation of the easy axis of magnetization in on the intention of the threshold for the outer the layer coincide. Lowering the switching field from this requirement results in a simultaneous extension the inequality for the angle et, which in 5 ° tion of the switching times as a result of the increasingly bringing-up connection The inconsistency of the process mentioned with the Swiss patent specification is not taken into account 745 was mentioned. is sighted.

Under the influence of larger switching fields, the object of the invention is to specify a strength or, more precisely, its vector via arrangement of the type described above, a critical curve, the so-called switching asteroid, 55 in which one extends between adjacent magnetic and which also a not too small layers (films) occurring, the coherent rota angle α according to the mentioned inequality with the tion of the magnetization vector promoting effect orientation of the easy magnetization axis is used to close in spite of a spatially close, is found in the designated layers (FiI - Lower stacking of the magnetic layers that men) the flux reversal as a result of the desired coherent rotation of the magnetization rent rotation of the magnetization vector within vector to maintain in each individual layer and take place for a few nanoseconds. Under the influence of the
the relevant control panel is the prescribed
Precession motion of the magnetization vector
thrown out of the easy axis, in the course of which 65
this vector seeks to leave the layer plane. at
the slightest deviation from the layer level goes
however, from the closely adjacent outer surfaces

thereby processing the greatest possible electrical power per unit volume of the arrangement can.

This object is achieved in that the thin, non-magnetic layer is a allows mutual magnetic influence of neighboring films and that the arrangement the magnetic

field in the bisector of the two bias directions Enclosed angle can be impressed so that the magnetization vectors of the adjacent films rotate in opposite directions.

Embodiments of the invention are shown in the drawing and are described below explained in more detail. The figures indicate the most important features of the invention. It shows

Fig. 1 is a view of the arrangement from the side,

When a driving field H acts along the easy central axis 32 of the layer 16 (FIG. 3), the magnetization M ₂ rotates through an angle σ ₂ · ^{η in the} direction of a position M ₂ ¹ . When the magnetization 5 _{leaves the easy axis M 2} , a component M ₂ ² is generated perpendicular to the plane of the layer. This creates a demagnetizing field which limits this component to extremely low values, so that the magnetization is essentially in the plane

can be measured according to FIGS. 4 and 5, respectively.

7 and 8 show two further embodiments of the invention, which act as a transformer or a choke coil work.

In Fig. 1, an arrangement 10 is shown schematically from the side. It consists of a base 12 of metal or glass bearing successive layers 14, 16 of a magnetic material,

2 shows the same arrangement from above, the 10 of the layer 16 rotating, as shown as curve 30. Location of the easy axes and the bias This mechanism is more detailed in the article: directions in the neighboring films are shown, »Amplifier and Memory Devices: With Films and Fig. 3 is a vector diagram for explaining the diodes ", McGraw-Hill Book Company, 1965, Kapi working method the arrangement according to the invention, tel 13, treated.

FIGS. 4 and 5 are further views of the arrangement of FIG. 15. When the biases of the layers in FIG above with different orientations of the easy axes all parallel to the easy axes would Axes and with different positions of the imposed field cause the magneto imprinted Magnetic field rotates in the same direction relative to the mean light sation of all layers; The axis of the entire arrangement and the perpendicular components would be inner pole pairs

Fig. 6 form two idealized 20 drawn one above the other, which cancel each other out, with only the Hysteresis loops, the poles on the top and bottom layers 16 not being deleted during operation of the arrangement

stayed. With a fairly large total thickness of the layers, a very weak demagnetizing would result Field approximating that of a compact, magnetizable body of the same thickness, so that the magnetization would be switched like that in a compact material.

In the present arrangement, however, the magnetization of layers 14 and 16 rotates in the direction that alternates with insulating layers 18, and 30 in the opposite direction, as can be seen from curves 30, in particular by a deposition method and 34, so that the inner pole pairs are in the Vacuum are produced, the z. B. in the USA.- M ₁ ² , M ₂ ² reinforce each other. This creates a strong, demagnetizing field in all layers in patents 2,900,282, 3,155,561 and 3,065,105. The layers 14, 16 are thin, of which the magnetization is switched on by the rotation of such ferromagnetic films with the property of a single layer, as is the case with a single layer, tens of domains of uniaxial anisotropy, whereby a thin, ferromagnetic film is the case. an easy axis is given along which the remanent Fig. 4 shows an arrangement 10a from above, which as

Magnetization in one or the opposite transformer or inductor core is used whichever direction lies. The thin layers 14, 16 from which the should. In this embodiment, the ferromagnetic films have the peculiarity 40 symbols M ₁ and M ₂ only the meaning of Magnetides rotational switching, as in the USA.- sierungsvektoren, which is not shown with the dashed Darge patent specification No. 3,030,612. made light axes coincide.

Figure 2 is a top plan view of assembly 10 in use at right angles to the central axis

and shows the orientation of the easy axis in the M _{0 applied} via a winding 42, an alternating field 40, different layers. The one set of alternating 45, whereby the magnetizations at the angle Q ₁ or ρ ₂ layers 14a, 14b, 14c and 14d (FIG. 1) oscillate about the central axis M _n. The arrangement easy axis M ₁ and the other set of layers therefore works as a choke coil or, after the addition of 16a, 16b, 16c and 16 "", an easy axis M _2. They add a secondary winding 44 as a transformer, both axes M ₁ and M ₂ Form a pointed, preferably the winding 42 creates a magneti-Winkel et, and the layers represent such a combined 5 ° sizing force ± //, the strength of which is just as great, as if they were together a single effective nation that the magnetizations M ₁ and M _{2 would have} at an angle easy central axis M ₂ , the point from the
two axes M ₁ , M ₂ halved angle formed,
if the layers are all similar. the
Halving line of an obtuse angle ß ' between 55
the two easy axes M ₁ , M ₂ represent a hard one
Central axis, which is to the easy central axis M _a
is orthogonal.

In Fig. 3 the tracks are shown schematically,
which, under the influence of an impressed field of 60 p. 262, is known, the individual, thin, ferromagnetic magnetization vectors in the layers 14, 16 are assigned to table films of uniaxial anisotropy. Here, the symbol M ₁ which are driven in the hard direction, both for the easy axis of the layer 14 and in FIG. 5, an arrangement 10b in the manner

used for their magnetization vector if this is used as a storage element for binary digits that vector lies in the easy axis. A similar symmetry 65 via a coil 52 to the central axis M _a is a bol with a Beiziffer such parallel. B. M ₁ ¹ , M ₁ ² is a driving field ± H is impressed, the magnitude of which reproduces the magnetization _{vector that is not in the magnetizations M 1} and M ₂ completely switched easy axis. will. The change in the magnetic flux in the

swing from ± 45 ° around the central axis M _a; the total change in flux in assembly 10a is then approximately 0.7 of the saturation flux.

In Fig. 6, there is an idealized ^ - // loop 60 for the Arrangement of Fig. 4 reproduced. It has an almost lossless shape that, like z. B. from the "Taschenbuch der Nachrichtenverarbeitung" by K. Steinbuch, Berlin / Göttingen / Heidelberg, 1962,

Order Wb during the switchover is perceived by a sensing coil 54, the axis of which is parallel to the central axis M _a . If the direction of the magnetizations in the two sets of layers 14 and 16, which are represented by solid arrows, means, for example, a stored one, a driving field applied via the coil 52 has the effect that the magnetizations are reversed by 180 ", i.e. the polarities reversed whereby a substantial signal appears in the sensing coil 54. Conversely, if the magnetizations are in the opposite direction, application of the driving field across the coil 52 produces only a weak signal in the sensing coil 54, which indicates the stored zero.

In Fig. 6 there is also a ^ - // loop 62 for the Arrangement 10ό shown when it operates as a memory in the manner explained above. This loop is essentially rectangular and provides an ideal ao characteristic for a magnetic storage element of binary digits.

7 shows a further embodiment of an arrangement 70 which is suitable as a transformer or inductor core. It consists of stacked layers 74a, 766, 746, 76b of a thin, ferromagnetic film, which are similar to layers 14, 16 of FIG. 1 and are separated from one another by insulating layers (not shown). All layers in this embodiment are in the form of flat rings. The layers 74, 76 have radial easy axes and their magnetizations are directed alternately inwards and outwards. By impressing an alternating field via a winding 72, the magnetizations M ₁ and M _{2 of} the layers 74, 76 are caused to oscillate in their radial directions as in the embodiment according to FIG. 4, whereby the magnetic flux through an output winding 78 changes when the device works as a transformer. The thin output winding can be omitted for use as a choke coil. The change in magnetic flux in assembly 70 passes through a loop similar to loop 60 in FIG.

FIG. 8 shows another arrangement in which the thin films are formed differently. In this case, a core 80 is constructed from several concentric cylinders 84, 86 in the form of a thin ferromagnetic film each, the adjacent layers of which are separated by insulating layers (not shown). The magnetizations of the successive cylinders 84, 86 are opposite to one another and run parallel to a common axis 81. As a result of the application of a drive field via an input winding 82, the magnetizations M ₁ and M _{2 of} the layers 84, 86 are rotated out of their easy axis, as a result of which a voltage arises in an output winding 88 in the case of a transformer. In the case of a choke coil, the winding 88 can be omitted.

1 sheet of COPY drawings

409 523/155

Claims (1)

Magnetization vectors (M ₁ , M ₂ ) at an angle Claims: of i45 ° with respect to the directions of bias are rotatable back and forth. 1. Arrangement of several stacked stacked, thin, ferromagnetic films of 5 uniaxial anisotropy, separated from each other by a thin, non-magnetic layer The invention relates to an arrangement of several of its easy axis in a first direction and several thin, ferromagnetic layers stacked one on top of the other along its light io-tic films of uniaxial anisotropy, the from-axis in a second direction are biased each other by a thin, non-magnetic, with a winding over which the films of the layer are separated, every second film of the stack a magnetic field can be impressed, the stack of which along its easy axis in a first direction with one or the other bias magnet - Direction and each intermediate film in the longitudinal direction includes an "angle at which 15 of its easy axis in a second direction are pre-magnetized with a coherent rotation of the magnetization, with a winding over which the gate can be achieved within a single film. Films of the stack a magnetic field can be impressed, u nd its strength for the coherent rotation out of its direction with one or the other advance, characterized in that the direction of magnetization includes an angle at which the thin, non-magnetic layer (18) is adjacent to a coherent rotation of the mutual magnetization vector within a single film is achievable, baked films (14a and 16a etc.) and and whose strength is sufficient for the coherent rotation that the arrangement (10, 10a, 10b) is the magnetic field from Swiss Patent 416 745 (40, 50) in the bisector of the two a so-called thin-film cell with anisotropic, bias directions included magnetic properties as well as the method for angles can be impressed, so that the magnetization, its manufacture and its operation are known. You berungsvektoren (M ₁ , M ₂ ) of the neighboring films is due to rotate through a non-magnetic intermediate layer (14a and 16a, etc.) in opposite directions. separate, magnetic layers, the light 2nd arrangement according to claim 1, characterized in that the axes with the externally appearing, characterized in that the Vormagnetisierungsrich- 30 easy axis of the entire cell the angle a / 2 lines of the adjacent films (14a and 16a, etc. .), which can amount to ^{a maximum of 25 r.} This win- form an acute angle (α) with one another and that the magnetization vectors (AZ ₁ , M ₂ ) of the adjacent films (14a and 16a, etc.) can be rotated by 180 ° from the magnetic field (50). 3. Arrangement according to claim 1, characterized in that the bias directions the adjacent films (14 a and 16 a, etc.) form a right angle with each other and that kel u results from the inequality: <a-2