RU2648948C1 - Combined element of magnetoresistive memory (options), ways of reading information from the element (options), ways of recording information on the element (options) - Google Patents

Abstract

FIELD: computer engineering.

SUBSTANCE: invention relates to computer engineering. MRAM element consists of n cells of MRAM, where n ≥ 3, each of the cells comprising at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) and at least one layer with a fixed direction of the magnetization vector (support layer), the light axis of the first cell of this MRAM element has a predetermined direction, and the direction of the easy axis of each subsequent cell is rotated relative to the previous cell by an angle equal to 2p/n±10 %, the angle between the cell with the number n and the first cell is also 2p/n±10 %.

EFFECT: technical result is to increase the safety of information in the elements on the bit cells of magnetoresistive memory (MRAM).

9 cl, 6 dwg

Description

FIELD OF TECHNOLOGY

The present invention describes a magnetoresistive memory element consisting of random access magnetic memory (MRAM) cells comprising a tunneling magnetic junction and having improved switching efficiency, lower power consumption, improved resistance to external magnetic fields, and providing reliable data readability. The present invention describes the multi-cell bits of MRAM and their configurations, as well as methods for writing information to them and methods for reading this information.

BACKGROUND

Various examples of manufacturing and working with MRAM memory cells protected from external magnetic fields are known in the art.

From the patent US6515352 (Micron Technology, Inc., 02/04/2003), a solution is known for protecting a magnetic conductor from external influences by using a casing of a magnetically sensitive material located on the surface of the conductor.

Patent US7489015 (Samsung Electronics Co., Ltd., 02/10/2009) discloses a memory device, in particular MRAM memory, containing a position protected against an external magnetic field.

Thus, at present, there is a need to manufacture an MRAM memory cell with stable protection against external magnetic influences, which will increase the stability of the memory medium and protect information from its loss.

SUMMARY OF THE INVENTION

The technical problem solved by the claimed technical solution is the implementation of the design of the MRAM memory element, which provides increased stability of the data recorded on this cell.

The technical result coincides with the solution of the technical problem and consists in increasing the safety of information in the elements on the bit cells of the MRAM memory.

Additionally, the task of monitoring the reliability of the information being read is also solved.

To implement the technical result in a preferred embodiment, a magneto-resistive memory element (MRAM) is declared, consisting of two MRAM cells, each of which contains at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) and at least one composite layer (reference layer), consisting of two oppositely directed magnetic layers with a fixed direction of the magnetization vector, the direction of which is determined by the layer closest to free layer, and the light axis of the cells are co-directional, regardless of the spatial arrangement of the cells, and the magnetization of the free layers of each of the cells are oppositely directed.

In another preferred embodiment, the claimed method of recording information on the above memory element, characterized in that in the process of recording information, the magnetization vectors of the free layer of each of the cells are changed so that they are opposite to each other.

In another preferred embodiment, a method for reading information from the above MRAM element is claimed, characterized in that the direction of magnetization of the free layers of each cell is determined, and if the magnetization of the cells is opposite to the direction, then the information is read from the element, otherwise it is believed that the information contained in the element, has lost its integrity and is not subject to reading.

In another preferred embodiment, an MRAM element is claimed consisting of n MRAM cells, where n ≥ 3, each cell containing at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) and at least one layer with a fixed direction magnetization vector (reference layer), while the easy axis of the first cell of this MRAM element has a given direction, and the direction of the easy axis of each subsequent cell is rotated relative to the previous cell by an angle equal to 2π⁄n ± 10%, the angle between the cell n and the first cell is also 2π⁄n ± 10%.

In another preferred embodiment, a method for recording information in the above MRAM memory element is claimed, characterized in that the direction of magnetization for the first cell is set along or opposite to the direction of magnetization of its reference layer (corresponds to a logical zero or one in the memory element), while for each cell with increasing the sequence number of the magnetization has a positive projection on the direction of magnetization of the previous cell.

In another preferred embodiment, the claimed method of reading information from a memory element, characterized in that they determine the direction of the magnetization vector of the free layer of each cell relative to its reference layer, determine the cells in which the direction of the magnetization vector of the free layer corresponds to logical zero and in which the direction of the magnetization vector of the free layer corresponds to a logical unit, while determining the state of the element as the state of most of its cells, and After the reading procedure, the state of all cells of the element is brought into correspondence with the determined state of the element.

In another preferred embodiment, a combined MRAM element is provided comprising two memory elements, each of which corresponds to the above construction of an MRAM element of n memory cells, each of the cells of the first mentioned element having a cell paired to it in the second mentioned element, in which the light axis of the cells are aligned , regardless of the spatial arrangement of the centers of the cells of the first and second memory elements, and the magnetization of the free layers of the cells of the first memory element and the corresponding their paired cells of the second memory element are oppositely directed.

In another preferred embodiment, the claimed method of recording information in the combined memory element described above, characterized in that in the first memory element specify the direction of magnetization along the easy axis of the first cell, determine the magnetization state for the first cell as logical 0 or logical 1, write information into the memory element so that the direction of magnetization along the easy axis of each subsequent cell relative to the previous one is identical to the state of the magnetization the first cell, and the directions of the magnetization vectors of the free layer of the cells of the second memory element are defined as oppositely directed to the directions of the magnetization of the free layer of the corresponding paired cells of the first memory element.

In another preferred embodiment, a method is disclosed for reading information from a combined memory element described above, characterized in that the direction of the magnetization vector of the free layer of each cell of the first memory element and the paired cell of the second memory element is determined, pairs of cells are determined for which the directions of the magnetization vectors are free layers are oppositely directed, the remaining paired cells are recognized as having lost information, and the state of the combined of a memory element is defined as the state of most cells of a combined memory element that have stored information, and if there are no such cells, then all of the mentioned combined element is considered to have lost information and cannot be read, and after the reading procedure, the state of all cells is brought into line with the specific state of the element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a sectional view of a memory cell.

FIG. 2 illustrates a view of a memory cell (top view).

FIG. 3 illustrates an embodiment of a combined MRAM element.

FIG. 4 illustrates an example of a logic operation when checking the integrity of a combined memory element.

FIG. 5 illustrates an example of a five-cell MRAM bit.

FIG. 6 illustrates an example of a combined paired MRAM bit.

DETAILED DESCRIPTION OF THE INVENTION

Magnetic random access memory (MRAM) uses magnetic rather than electrical effects to store bits of information. The use of magnetic memory in most cases allows you to increase the performance of electronic devices, allowing you to store large amounts of information and at the same time have a fairly fast write / read time, do not require high power consumption (compared to other types of memory). In addition, MRAM allows you to save information even when the power is off, allowing electronic devices running on the basis of MRAM to start instantly, unlike devices with conventional electronic memory, which require preliminary initialization to load software into memory.

A typical element (chip) of magnetic memory includes an array of cells. The memory cells may include a layer of magnetic material with a variable orientation of the magnetization vector and a layer of magnetic material, in which the magnetization vector has a fixed direction. A layer with a variable orientation of the magnetization vector is used to store information and is often referred to in the literature as a free layer (FL - free layer or sometimes SL - sence layer). A layer with a fixed direction of the magnetization vector is called a reference layer (RL - reference layer).

The resistance of the MRAM magnetic memory cell in the parallel and antiparallel positions of the free and reference layers is different due to the tunnel magnetoresistance (TMR) effect. Thus, logical “0” - the position of the lower resistance and “1” - the position of the higher resistance (the reverse definition is possible) are determined in the MRAM memory cells.

и энергетический барьер. Критическое поле – это поле переключения ячейки при нулевой температуре при данном направлении магнитного поля. Энергетический барьер (

) – это разность между значениями в минимуме и в барьере. Значение энергии в барьере определяется как значение максимальной энергии в минимальном пути между двумя положениями минимума энергии. There are two parameters that determine the stability of a cell; this is a critical field.

and energy barrier. The critical field is the cell switching field at zero temperature for a given direction of the magnetic field. Energy Barrier (

) Is the difference between the minimum and the barrier. The energy value in the barrier is defined as the value of the maximum energy in the minimum path between the two positions of the minimum energy.

) в единицах постоянной Больцмана (

):The energy barrier determines such an important parameter as the temperature stability parameter delta (Δ). This parameter is equal to the ratio of the energy barrier that must be overcome by the magnetization of the free layer of the memory cell in order to switch between two stable states of the memory cell (corresponding to logical “zero” and “one”), to the cell temperature (

) in units of the Boltzmann constant (

):

The parameter of temperature stability of memory cells allows you to determine the probability of spontaneous switching of memory cells. To do this, use a simple formula obtained from the Boltzmann distribution:

Usually, the smaller the critical field, the lower the energy barrier, however, the relationship between them can be non-linear and include a number of additional parameters (cell size, angle at which the field is directed, etc.).

, критическое поле может упасть в два раза. Соответственно, энергетический барьер может упасть в два раза и более, кроме того, барьер может и вовсе исчезнуть. Зависимость критического поля от направления для идеализированной ячейки памяти MRAM описывается так называемой теорией Стонера-Вольфарта (Stoner-Wohlfarth).Switching the MRAM memory cells can be carried out in various ways, including switching due to the transfer of magnetic moment by spin current, switching by a magnetic field, switching by a magnetic field using heating, as well as some other methods. In addition to the planned switching, the MRAM memory cells can switch unplanned, this can especially be manifested in a strong external magnetic field. Thus, MRAM memory chips can undergo errors in the presence of an external spurious magnetic field. This is due to the fact that in the presence of an external magnetic field, the energy barrier of the MRAM cells separating the two equilibrium positions corresponding to the logical “0” and “1” changes and the cell can spontaneously move from one position to another, which will lead to loss of information. Moreover, the change in the energy barrier depends not only on the magnitude of the spurious external magnetic field, but also on its direction. So, with a field directed at an angle

, the critical field can fall by half. Accordingly, the energy barrier can fall twice or more, in addition, the barrier can disappear altogether. The dependence of the critical field on the direction for an idealized MRAM memory cell is described by the so-called Stoner-Wohlfarth theory.

по отношению к легкой оси. For real applications, the external magnetic field can be directed in an arbitrary direction, therefore, to calculate the energy barrier, it is necessary to focus on the direction that reduces the barrier most strongly - the worst direction. Thus, for one cell, this is the direction of the external magnetic field

in relation to the easy axis.

In FIG. 1 is a perspective view of an MRAM cell 100 according to a first preferred embodiment. Cell 100 contains at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) 110 and at least one composite layer (support layer) 120, consisting of two oppositely directed magnetic layers 120a, 120b with a fixed direction of the magnetization vector 121, 122, the direction of which is determined by the layer 120a closest to the free layer 110.

According to FIG. 2, cell 100 may be of various shapes (rectangular, elliptical, etc.).

In FIG. Figure 3 shows an example of the implementation of the combined memory element MRAM 10, consisting of two cells 100 and 200. The light axis 130, 230 of the memory cells are co-directional, while the magnetizations of the free layers 111, 211 are oppositely directed.

In FIG. 4 shows an example of the operation of the logic of the combined element MRAM 10.

In the process of recording information (can be carried out both by a magnetic field and by a spin-polarized current) onto an MRAM element 10, consisting of two memory cells 100, 200, the magnetization vectors 111, 211 of the free layer 110, 120 of each of the cells 100, 200 are changed so that they are oppositely directed towards each other.

The up and down positions shown in FIG. 4, correspond to more and less resistance of the structure. This difference is achieved due to the effect of tunnel magnetoresistance. The logic of the work is that if the magnetization vectors in memory cells 100, 200 are oppositely oriented, then the data stored in this bit of memory 10 can be trusted. If the orientation of the magnetization vectors 111, 211 coincides, this will mean that the bit was exposed to an external magnetic field and lost the information stored in it and it is impossible to trust the data from this bit 10.

When reading information from the MRAM memory element 10, which consists of two memory cells 100, 200, the direction of the magnetization vectors of free layers 111, 211 of each of the cells 100, 200 is determined, during which it is established whether the direction of the magnetization vector has changed in comparison with the direction of the magnetization of free layers 111, 211 of cells 100, 200 when recording information on the MRAM element 10. If the magnetization of cells 100, 200 is oppositely directed, then the information is read from the MRAM element 10, because the integrity of the information stored on it is not violated. Otherwise, when determining the magnetization of the free layers of cells 100, 200, which changed its direction to codirectional, the information contained in element 10 is recognized as having lost its integrity due to the influence of a magnetic field and cannot be read.

(где n=5). Угол между последней ячейкой 500 и первой 100 также равен

. In FIG. 5 shows an example of a combined bit (element) of MRAM 20, consisting of n number of cells 100-500, where n is greater than or equal to three, in particular, of five memory cells 100-500. The memory element 20 is created by combining five cells 100-500 MRAM, arranged so that each subsequent cell 100-500 relative to the previous one is rotated by an angle

(where n = 5). The angle between the last cell 500 and the first 100 is also equal

.

The number of cells can be different in element 20, the main thing in this structure is the observance of the position of cells 100-500 relative to each other, and the number of cells n must be greater than or equal to three.

), который должен быть преодолен намагниченностью 111 свободного слоя 110 ячейки памяти 100 для того чтобы произошло переключение между двумя стабильными состояниями ячейки памяти (состояния отличаются по уровню сопротивления, которое достигается благодаря эффекту туннельного магнитосопротивления, и соответствуют логическим «нулю» и «единице»), к температуре (

) ячейки в единицах постоянной Больцмана (

):The ability to store information for the 100 MRAM memory cell is determined by the so-called delta temperature stability parameter (Δ). This parameter is equal to the ratio of the energy barrier (

), which must be overcome by the magnetization 111 of the free layer 110 of the memory cell 100 in order to switch between two stable states of the memory cell (the states differ in the level of resistance, which is achieved due to the effect of tunnel magnetoresistance, and correspond to logical “zero” and “unity”) to temperature (

) cells in units of the Boltzmann constant (

):

(1)

(one)

должен составлять от 45 до 60 для массивов от 100 бит до 500 Мбит. In order for the memory array to store information for 10 years, the required minimum level

Must be between 45 and 60 for arrays from 100 bits to 500 Mb.

зависит от энергетического барьера в ячейке памяти, который является чувствительным к воздействию внешнего магнитного поля

. Если зафиксировать направление магнитного поля либо сонаправленно с легкой осью ячейки памяти или перпендикулярно ей, то зависимость примет следующий вид [A.V. Khvalkovskiy, J. Phys. D: Appl. Phys., 2013]:It is important to recall that

depends on the energy barrier in the memory cell, which is sensitive to the effects of an external magnetic field

. If we fix the direction of the magnetic field either co-directionally with the easy axis of the memory cell or perpendicular to it, the dependence will take the following form [AV Khvalkovskiy, J. Phys. D: Appl. Phys., 2013]:

(2)

(2)

есть поле анизотропии, определяющееся выражениемHere

is the anisotropy field defined by the expression

, (3)

, (3)

– плотность энергии анизотропии, а

– намагниченность насыщения. Where

Is the energy density of anisotropy, and

- saturation magnetization.

, так и в том же направлении, увеличивая энергетический барьер и

. При этом

. Таким образом, внешнее магнитное поле приводит к уменьшению стабильности одного из двух стационарных состояний ячейки памяти 100 MRAM, вплоть до того, что при

энергетический барьер исчезает и у ячейки 100 остается всего одно стабильное состояние. Different signs indicate that different directions of the external magnetic field can act against the anisotropy field, thereby reducing the energy barrier and

in the same direction, increasing the energy barrier and

. Wherein

. Thus, an external magnetic field leads to a decrease in the stability of one of the two stationary states of the 100 MRAM memory cell, up to the point that when

the energy barrier disappears and cell 100 has only one stable state.

. Как видно из формулы выше, для внешнего магнитного поля сонаправленного с легкой осью 103 или перпендикулярного ей, критическое поле равно полю анизотропии, то есть

. Such a field is called critical and is denoted by

. As can be seen from the formula above, for an external magnetic field co-directional with the easy axis 103 or perpendicular to it, the critical field is equal to the anisotropy field, i.e.

.

достигается при угле между легкой осью ячейки и магнитным полем

и составляет порядка половины от значения при

(например, для ячеек эллиптического сечения, по так называемой теории Стонера-Вольфарта,

для

и составляет ровно половину от значений при

).Smallest value

achieved at an angle between the light axis of the cell and the magnetic field

and is about half of the value at

(for example, for cells of an elliptical cross section, according to the so-called Stoner-Wolfart theory,

for

and is exactly half of the values for

)

аналогично выше описанному:The temperature dependence parameter, taking into account the angle of inclination of the magnetic field vector to the easy axis, is related to the critical field

similar to the above described:

(4)

(four)

при изменении угла наклона вектора магнитного поля к легкой оси 130-530 ячеек 100-500 существенно влияет на величину барьера. Например, для ячейки 100, которая в отсутствии магнитного поля имеет

и

, что обеспечивает время жизни массива из миллиона ячеек более чем в

лет при комнатной температуре в отсутствии внешнего магнитного поля. При наличии внешнего магнитного поля

, сонаправленного с легкой осью 130 ячейки 100 или перпендикулярного ей, дельта уменьшается до значения

, что приводит к тому, что массив из миллиона ячеек имеет время хранения информации (все биты массива сохраняют свою информацию)

лет. Если же изменить направление магнитного поля на

, то дельта сократится до значения

, и время хранения информации массива из миллиона ячеек сократится до 10 миллисекунд. Так как внешнее магнитное поле может быть направленно произвольно, то для оценки стабильности ячейки необходимо рассматривать наихудшее направление. Поэтому в рассматриваемом выше примере можно прийти к выводу, что данная ячейка будет не стабильна в магнитном поле в 100 эрстед.As can be seen from this formula, the fall

when the angle of inclination of the magnetic field vector to the easy axis 130-530 cells 100-500 changes significantly affects the value of the barrier. For example, for cell 100, which in the absence of a magnetic field has

and

, which ensures the lifetime of an array of a million cells in more than

years at room temperature in the absence of an external magnetic field. In the presence of an external magnetic field

aligned with the easy axis 130 of cell 100 or perpendicular to it, the delta decreases to a value

, which leads to the fact that an array of a million cells has an information storage time (all bits of the array retain their information)

years. If the direction of the magnetic field is changed to

, then the delta will decrease to

, and the storage time of an array of a million cells will be reduced to 10 milliseconds. Since the external magnetic field can be directed arbitrarily, to assess the stability of the cell, it is necessary to consider the worst direction. Therefore, in the example considered above, we can conclude that this cell will not be stable in a magnetic field of 100 Oersteds.

The proposed technical solution allows leveling the influence of the direction of the external magnetic field on the stability of the MRAM 10 (20) memory bit, which consists of two or more memory cells, and also allows you to control the accuracy of the information stored in the bit.

, обладает практически такой же устойчивостью к внешнему паразитному магнитному полю произвольного направления, что и одна ячейка к внешнему магнитному полю с фиксированным направлением магнитного поля вдоль оси перемагничивания или перпендикулярного ей. Таким образом, данная схема позволяет практически полностью нивелировать зависимость стабильности элемента памяти MRAM 20 от направления внешнего паразитного магнитного поля. Obtained by the above method, the combined element MRAM 20 from a plurality of cells 100-500 uniformly distributed over

, has almost the same resistance to an external parasitic magnetic field of arbitrary direction as one cell to an external magnetic field with a fixed direction of the magnetic field along the magnetization reversal axis or perpendicular to it. Thus, this scheme makes it possible to almost completely level the dependence of the stability of the MRAM 20 memory element on the direction of the external parasitic magnetic field.

To determine the integrity of the information stored in the memory element MRAM 20, the integrity of all cells 100-500 included in it is checked. The operating principle of the logic is similar to the method shown in FIG. 4. The logic of work is that if the magnetization vectors in memory cells 100-500 are oppositely oriented, then the data stored in this bit of memory 20 can be trusted. If the orientation of the magnetization vectors of cells 100-500 coincides, this will mean that bit 20 has been exposed to an external magnetic field and has lost the information stored in it and data from bit 20 cannot be trusted.

The method of recording information in the memory element MRAM 20 is that the direction of magnetization for the first cell 100 is set along or opposite the direction of magnetization of its reference layer (corresponds to a logical zero or one in the memory element), while for each cell 200-500 element MRAM 20 with increasing serial number, the magnetization has a positive projection on the direction of magnetization of the previous cell. The direction of magnetization of the support layer of cells, in particular, is performed by heating in a magnetic furnace above the Curie temperature in the presence of a strong magnetic field. The direction of magnetization of the free layer can be specified both by the local action of a magnetic field (due to the passage of current through current lines near the cell) and by the action of a spin-polarized current.

When reading the information of their memory element 20, the direction of the magnetization vector of the free layers of each cell 100-500 relative to their reference layers is determined, while the test determines cells 100-500, in which the direction of the magnetization vector of the free layer corresponds to logical zero and in which the direction of the magnetization vector a free layer corresponds to a logical unit. The state of the MRAM element 20 is determined as the state of the majority of cells 100-500 included in it, and, after the reading procedure, the state of all cells 100-500 of the element 20 is brought into correspondence with the determined state of the element 20 at the time of recording information on it, which allows restoration lost information in such memory cells.

The worst direction of the magnetic field for the memory element MRAM 20 is that in which information will be lost in most of the memory cells 100-500 MRAM included in the combined memory element 20, for example, if the information is lost in three out of five memory cells. Otherwise, information can be restored by the value of the data in most cells 100-500, i.e. according to their initially determined condition.

(в зависимости от

для ячейки) в отсутствии магнитного поля и поля анизотропии ячейки

, что будет соответствовать увеличению времени жизни ячейки в определенном состоянии на

порядков по сравнению с наихудшим случаем для обыкновенной ячейки (при угле наклона магнитного поля к легкой оси в

). Для любого другого направления падение критического поля для четырех из пяти ячеек 100-500 будет выше, чем для указанного направления и комбинированный элемент (бит) памяти 20 будет еще более стабилен. In this case, for two memory cells 100, 200 out of five, the critical field decreases by 30% of the maximum, and for the remaining three 300-500 it does not change or even increases. Accordingly, an increase in the barrier for the described case of the combined memory bit 20 will correspond to an increase in the delta by approximately

(depending on the

for a cell) in the absence of a magnetic field and anisotropy field of the cell

, which will correspond to an increase in the cell lifetime in a certain state by

orders of magnitude compared with the worst case for an ordinary cell (at an angle of inclination of the magnetic field to the easy axis in

) For any other direction, the fall of the critical field for four out of five cells 100-500 will be higher than for the specified direction and the combined element (bit) of memory 20 will be even more stable.

является наихудшим направлением поля. При этом критическое поле

будет составлять 0.7 от максимального, достигаемого при сонаправленном положении вектора направления внешнего магнитного поля и легкой оси 130-530 ячеек 100-500, что на 40% выше, чем для одиночной ячейки памяти с теми же параметрами. Соответственно, падение барьера от угла наклона вектора магнитного поля к легкой оси 130-530 для описанного выше случая будет соответствовать уменьшению дельты до значения

, таким образом, время хранения информации массива из миллиона ячеек будет составлять 6 дней при внешнем магнитном поле в 100 Oe, что более чем на 7 порядков больше, чем для наихудшего случая обыкновенной ячейки. For example, the element MRAM 20

is the worst field direction. In this case, the critical field

will be 0.7 of the maximum achieved with the co-directional position of the direction vector of the external magnetic field and the easy axis of 130-530 cells 100-500, which is 40% higher than for a single memory cell with the same parameters. Accordingly, a drop in the barrier from the angle of inclination of the magnetic field vector to the easy axis 130-530 for the case described above will correspond to a decrease in the delta to the value

Thus, the storage time of information from an array of a million cells will be 6 days with an external magnetic field of 100 Oe, which is more than 7 orders of magnitude than for the worst case of an ordinary cell.

меньше чем для одиночной ячейки памяти MRAM с теми же характеристиками, что приведет к увеличению времени хранения информации на

порядков.Accordingly, the fall of the barrier from the angle of inclination of the magnetic field vector to the easy axis 130-530 for the worst case of the combined memory element 20 will be

less than for a single MRAM cell with the same characteristics, which will lead to an increase in the storage time of information on

orders.

In FIG. 6, another preferred embodiment of the claimed solution is presented, which consists in combining the previous ones, in particular, the architecture of the combined memory element MRAM 30 is proposed, which contains two combined memory elements 30a and 30b, each of which is similar to the memory element MRAM 20. Each of the cells 100a -500a of cell 30a has a cell 100b-500b of element 30b paired with it, in which the light axes of the respective cells are co-directional, regardless of the spatial arrangement of the centers of the cells 100a -500a and 100b-500b, and the magnetizations of the free layers of cells 100a-500a and their corresponding paired cells 100b-500b are oppositely directed.

Presented in FIG. 6, the cell arrangement of the MRAM element 30 may differ (while maintaining the relative cell orientation). So, for example, the location of cells along in a circle or along a straight line will have the same meaning. Arrows indicate the direction vectors of magnetization.

The combination of the above described examples of the combination of elements MRAM 10 and 20 in the design of the element 30 allows you to read information from such bits of MRAM 30 even if 4 of the 5 paired memory cells have changed orientation to codirectional. Thus, the stability of this bit to the effects of an external magnetic field turns out to be very high - the bit will lose information when the field magnitude almost coincides with the magnetization reversal field in the absence of an inclination of the external magnetic field vector to the magnetization vector of the memory cell, which is 2 times higher than for one cell in the direction π / 4 magnetic field to the cell magnetization vector. In General, this design has approximately the same level of stability as described in the previously combined cell, however, the ability to verify the reliability of the recorded information is an extremely important advantage of the design of the memory element 30.

The method of recording information in the memory element 30 is that in the first element 30a the direction of magnetization is set along the easy axis of the first cell 100a, the magnetization state is determined for the first cell 100a as logical 0 or logical 1. Subsequently, information is recorded in the memory element 30a in this way so that the direction of magnetization along the easy axis of each subsequent cell 200a-500a relative to the previous cell is identical to the state of magnetization of the first cell 100a, and the directions of the magnetization vectors con- cern free layer 100b 500B 30b-element cells are defined as the opposing directions of magnetization of the free layer of the respective paired cells 100a-500a member 30a.

To read information from a memory element, MRAM 30 consists in determining the direction of the magnetization vector of the free layer of each cell 100a-500a and its paired cell 100b-500b. Then, pairs of cells are determined for which the directions of the magnetization vectors of the free layers are oppositely directed, the remaining paired cells are recognized as having lost information, and the state of the mentioned combined memory element 30 is defined as the state of most cells of the memory element that have saved information, and if there are no such cells, then the whole combined the MRAM 30 element is considered to have lost information and cannot be read, and after the reading procedure, the state of all cells is brought into correspondence an event with a certain state of an element.

A method of initializing the reference layers of memory cells can also be applied using the example of the MRAM 20 element, in which the cells are heated to a temperature above the Néel temperature in the presence of a magnetic field with a given power directed along the first cell 100 of the mentioned MRAM 20 element, then the heating temperature and the magnetic field power are reduced .

The implementation options of the claimed technical solution presented in the present application materials disclose preferred aspects of its implementation and should not be used as limiting other, private implementation options that are obvious to a person skilled in the art, not going beyond the scope of the legal protection.

Claims (9)

1. Magnetoresistive memory element (MRAM), consisting of two MRAM cells, each of which contains at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) and at least one composite layer (reference layer), consisting of two oppositely directed magnetic layers with a fixed direction of the magnetization vector, the direction of which is determined by the layer closest to the free layer, and the light axis of the cells are codirectional, regardless of the spatial aspolozheniya cells, and the magnetization of the free layer of each cell are oppositely directed. 2. The method of recording information on a memory element according to claim 1, characterized in that in the process of recording information, the magnetization vectors of the free layer of each cell are changed so that they are oppositely directed to each other. 3. The method of reading information from an MRAM element according to claim 1, characterized in that the direction of magnetization of the free layers of each cell is determined, and if the magnetization of the cells is oppositely directed, then the information is read from the element, otherwise it is believed that the information contained in element, has lost its integrity and is not subject to reading. 4. MRAM element, consisting of n MRAM cells, where n ≥ 3, each cell containing at least one layer of magnetic material with a variable orientation of the magnetization vector (free layer) and at least one layer with a fixed direction of the magnetization vector (reference layer), while the easy axis of the first cell of this MRAM element has a specified direction, and the direction of the easy axis of each subsequent cell is rotated relative to the previous cell by an angle equal to

while the angle between the cell number n and the first cell is also

. 5. The method of recording information in a memory element according to claim 4, characterized in that the direction of magnetization for the first cell is set along or opposite to the direction of magnetization of its reference layer (corresponds to a logical zero or one in the memory element), while for each cell with increasing ordinal the magnetization number has a positive projection on the direction of magnetization of the previous cell. 6. The method of reading information from a memory element according to claim 4, characterized in that the direction of the magnetization vector of the free layer of each cell relative to its reference layer is determined, cells are determined for which the direction of the magnetization vector of the free layer corresponds to logical zero and for which the direction of the magnetization vector of the free the layer corresponds to a logical unit, while determining the state of the element as the state of the majority of its cells, and after the reading procedure, the state in all cells of an element are brought into correspondence with a certain state of an element. 7. A combined MRAM element containing two memory elements according to claim 4, wherein each of the cells of the first mentioned element has a cell paired to it in the second mentioned element, in which the light axis of the cells are co-directional, regardless of the spatial arrangement of the cell centers of the first and second elements memory, and the magnetization of the free layers of the cells of the first memory element and the corresponding paired cells of the second memory element are oppositely directed. 8. The method of recording information in the combined memory element according to claim 7, characterized in that in the first memory element the direction of magnetization is set along the easy axis of the first cell, the state of magnetization is determined for the first cell as logical 0 or logical 1, information is recorded in the memory element so that the direction of magnetization along the easy axis of each subsequent cell relative to the previous one is identical to the state of magnetization of the first cell, and the directions of the magnetization vectors the free layer of the second memory cells are defined as the element oppositely directed directions of magnetization of the free layer of the respective paired memory cells of the first element. 9. The method of reading information from the combined memory element according to claim 7, characterized in that they determine the direction of the magnetization vector of the free layer of each cell of the first memory element and paired cells of the second memory element, determine the pairs of cells in which the directions of the magnetization vectors of the free layers are opposite directed, the remaining paired cells are recognized as having lost information, and the state of the combined memory element is defined as the state of most cells a binded memory element that has retained information, and if there are no such cells, then all of the mentioned combined element is considered to have lost information and cannot be read, and after the reading procedure, the state of all cells is brought into line with the specific state of the element.

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