JPH04305887A - Driving method for bloch line memory element - Google Patents

Abstract

PURPOSE:To shorten the rewriting time of information. CONSTITUTION:Major/minor constitution can be formed by arranging a minor loop 32 on a major line 20 at every other bit. A write bubble string is stopped at position '1' before one bit of a write position '0', and is segmented as a bubble to erase a pair of Bloch lines on the minor loop 32, and is housed in a null bit on the major line. Then, the bubble string is transferred by one bit, and write data is advanced to a bit position '0', then a write operation is performed. Residual bubble string is deleted by transferring to the right. Thereby, it is possible to perform the erasure and write of the pair of Bloch lines simultaneously by one time of transfer of the bubble.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a nonvolatile ultra-high density magnetic memory element, a Bloch line memory element.

0002

[Prior Art] As an ultra-high-density solid-state magnetic memory element that replaces a magnetic bubble memory element, boundaries between striped magnetic domains existing in a ferromagnetic (including ferrimagnetic) film whose easy magnetization direction is perpendicular to the film surface are formed. A Bloch line memory element was invented that uses a Bloch line pair (hereinafter referred to as a VBL pair) consisting of two vertical Bloch lines stably existing in a Bloch domain wall as a memory unit (Japanese Patent Application No. 57-182346). .

In the Bloch line memory device, information is written in the form of VBL pairs along the Bloch domain wall around the stabilized stripe domain that constitutes the major line and minor loop for inputting and outputting information, and the VB
It is essential to have a means for reading the information unit represented by a minute area called an L pair, and a means for transferring and holding the VBL pair bit by bit on the minor loop.

Generally, a ring-shaped stripe domain is used for the stripe domain, and a two-layer stripe conductor or one layer of stripe conductor and one layer of magnetic material pattern is used for the major line. A specific example is shown in FIG.

In FIG. 3, 10 is a garnet layer which is a striped magnetic domain retention layer, 20 is a major line, and 30 is a minor loop. The measure line 20 is composed of two layers of scalloped conductors 21 and 22 and a shallow groove 23 dug into the garnet layer. The minor loop 30 is composed of a shallow groove 31 dug into the garnet layer and a stabilized ring-shaped stripe domain 32 inside the groove. The major line 20 and the minor loop 30 are connected via a write/read/erase gate 25.

The conventional method of driving a Bloch line memory element will be explained with reference to FIG. It is transferred from left to right on the major line 20 and stops at the minor loop junction. Here, the write/read/erase gates are operated to write information into the minor loop 30 in the form of VBL pairs. To read the written information, press Write/
The read/erase gate is operated to convert the presence or absence of a VBL pair into the presence or absence of a bubble magnetic domain and extract it onto the major line.
The bubble magnetic domain 11 is transferred by a two-layer scalloped conductor and detected by a bubble detector located on the right side of the major line. Since the read gate acts as a replicate gate, the read is non-destructive.

[0007]

SUMMARY OF THE INVENTION In order to rewrite part or all of the information written in the minor loop, the VBL pair on the minor loop must be deleted in advance. It is difficult to eliminate VBL pairs on a minor loop, and it is common to exclude VBL pairs from outside the loop. This must be performed separately from the write operation, which increases the time required for the information rewrite operation and causes a decrease in memory performance.

An object of the present invention is to provide a method for driving a Bloch line memory device that solves this problem.

[0009]

[Means for Solving the Problem] The gist of the present invention is to provide information on perpendicular Bloch line pairs existing in a ferromagnetic (including ferrimagnetic) film whose easy magnetization direction is perpendicular to the film surface. A major/minor type Bloch line memory element having a major line for transferring the bubble magnetic domain existing in the ferromagnetic film, and a minor loop arranged through a write/erase gate every other bit of the major line. In the driving method, the bubble string transferred on the major line according to the write data is stopped n bits (n is an odd number) before the bit position where the write operation is performed to perform the erase operation, and then the bubble string is transferred n bits before the write operation is performed. It is to transfer and perform a write operation.

0010

[Operation] The write bubble string for the minor loop arranged every other bit on the major line is arranged every other bit on the major line, and in order to erase the VBL pair from the minor loop to this vacant bit position. A pseudo swap operation can be performed by accommodating the cut out bubble. Thereby, the erase operation and write operation of the VBL pair can be performed almost simultaneously.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a pulse waveform diagram showing an embodiment of the present invention. FIGS. 2A, 2B, and 2C are pattern diagrams showing information rewriting operations. The present invention is illustrated in FIGS. 1 and 2.
To explain using , the bubble train generated by the bubble generator on the upper left side of the major line 20 as shown in FIG. is transferred from left to right, and the bit position 1 is one bit before the minor loop junction 0 at the right end of Figure 2.
Stops at. Here, the gate is operated as an erase gate using the erase signal 43 in FIG. 1, and the VBL pair on the minor loop 32 is cut out as a bubble on the major line as shown in FIG. 2(b). Next, the transfer signal 42 of FIG. 1 is output for one bit, and the bubble string on the major line is advanced by one bit as shown in FIG. 2(c). Here, the write signal 44 in FIG.
The gate is operated as a write gate and the VBL pair is written onto the minor loop. The bubble row remaining on the major line is transferred to the right and erased by the detector. As described above, information is rewritten by one bubble train transfer.

[0013] In the case of a memory block with 1024 minor loops, 1 [MHz] major line transfer clock, and 100 [μs] gate operation time, it conventionally took 2.3 [ms] to rewrite the information of one address. However, in this embodiment, it was shortened to 1.3 [ms].

[0014]

[Effects of the Invention] As described above, the present invention takes advantage of the fact that during a write operation, the bubble rows on the major line are every other bit, and performs the erase operation and the write operation by shifting an odd number of bits and performing one bubble row transfer. This makes it possible to shorten the time required to rewrite information.

[Brief explanation of the drawing]

FIG. 1 is a pulse waveform diagram showing an embodiment of the present invention.

FIG. 2 is a pattern diagram showing the process of rewriting information.

FIG. 3 is a pattern diagram showing an example of a conventional Bloch line memory element.

[Explanation of symbols]

1 to 6 bit positions 10 Garnet film 11 as stripe domain retention layer Bubble magnetic domain 20 Major lines 21, 22 Linear conductor 23 Major line groove 25 Gate 26 Conductor pattern 30 Minor loop 31 Minor loop groove 32 Ring-shaped stripe domain 33 Stripe domain 41 Clock 42 Transfer signal 43 Erase signal 44 Write signal

Claims (1)

[Claims] 1. A pair of perpendicular Bloch lines existing in a ferromagnetic (including ferrimagnetic) film whose easy magnetization direction is perpendicular to the film surface is used as an information carrier, and a bubble existing in the ferromagnetic film is used as an information carrier. In a method for driving a Bloch line memory element using a major/minor method in which a major line for transferring magnetic domains and a minor loop is arranged via a write/erase gate every other bit of the major line, data is transferred on the major line according to write data. A bloch characterized in that the erase operation is performed by stopping the bubble string n bits (n is an odd number) before the bit position where the write operation is performed, and then the write operation is performed by transferring the bubble string by n bits. A method of driving line memory elements.