Thermally assisted MRAMs: ultimate scalability and logic functionalities

Prejbeanu, I. L.; Bandiera, S.; Alvarez-Herault, Jérémy; Sousa, R. C.; Diény, B.; Nozières, J. P.

doi:10.1088/0022-3727/46/7/074002

Cited by 103 publications

(68 citation statements)

References 69 publications

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“…Research interests in spintronic memristor stem from the recent advances in the development of the spin-transfer torque (STT) random access memory technologies [57,58]. The fundamental physics behind STT is that when applying a current through a magnetic layer, the spins of electrons that constitute the current will be aligned to the magnetization orientation, which is known as spin-polarization, and these spins can be repolarized if such a spin-polarized current is directed into another magnet.…”

Section: Spintronic Memristormentioning

confidence: 99%

Overview of emerging memristor families from resistive memristor to spintronic memristor

Wang

Yang

Wen

et al. 2015

J Mater Sci: Mater Electron

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Memristor is a fundamental circuit element in addition to resistor, capacitor, and inductor. As it can remember its resistance state even encountering a power off, memristor has recently received widespread applications from non-volatile memory to neural networks. The current memristor family mainly comprises resistive memristor, polymeric memristor, ferroelectric memristor, manganite memristor, resonant-tunneling diode memristor, and spintronic memristor in terms of the materials the device is made of. In order to help researcher better understand the physical principles of the memristor, and thus to provide a promising prospect for memristor devices, this paper presents an overview of memristor materials properties, switching mechanisms, and potential applications. The performance comparison among different memristor members is also given.

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Section: Spintronic Memristormentioning

confidence: 99%

Overview of emerging memristor families from resistive memristor to spintronic memristor

Wang

Yang

Wen

et al. 2015

J Mater Sci: Mater Electron

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“…For more than twenty years, the interfacial exchange coupling between a ferromagnetic (F) and an antiferromagnetic (AF) layer, known as exchange bias [1], has been exploited in various technological applications like spin valves [2] or Magnetic Random Access Memories (MRAM) [3].…”

Section: Introductionmentioning

confidence: 99%

Focused Kerr measurements on patterned arrays of exchange biased square dots

Vinai

Moritz

Gaudin

et al. 2014

EPJ Web of Conferences

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Abstract. Microstructural effects on the antiferromagnetic layer were investigated on IrMn/Co exchange biased square dots. IrMn grain size and distributions were tuned by changing Cu buffer layer or IrMn thicknesses. Lateral dimensions from 200 to 50nm were varied. Exchange bias (H ex ) variability was analysed through focused Kerr measurements on small groups of dots. Patterned samples presented average exchange bias values following the trends and values of full sheet samples. Concerning the dot to dot behaviour, it resulted that IrMn microstructure variations have minor effects on H ex variability, because no particular trend is observed as a function of grain size and distribution. The variability is attributed to geometry variation and Co intrinsic variability.

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“…Therefore, it is important to know the relation between temperature and voltage by other means. As an example, this has been recently investigated using the spin-wave thermal population as a temperature probe [15].In Thermally Assisted MRAM (TA-MRAM) [7][8][9], the storage layer is pinned by exchange bias to an antiferromagnetic (AF) layer. When a current is sent through the MTJ, Joule effect heats the MTJ above the blocking temperature (Tb) of the AF.…”

mentioning

confidence: 99%

“…In all cases, the readout is performed by measuring at low bias voltage (~0.2V) the resistance of the MTJ which differs in parallel and antiparallel magnetic configuration due to the tunnel magnetoresistance phenomenon (TMR). Depending on the current amplitude, pulse duration and MTJ resistance, the current can also increase the temperature because of the power dissipated in the line or in the junction [7][8][9]. Solutions to reduce the current flow and the associated power consumption are currently under investigation, in particular by using the voltage control of magnetic anisotropy [10].…”

mentioning

confidence: 99%

Steady State and Dynamics of Joule Heating in Magnetic Tunnel Junctions Observed via the Temperature Dependence of RKKY Coupling

et al. 2016

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Understanding quantitatively the heating dynamics in magnetic tunnel junctions (MTJ) submitted to current pulses is very important in the context of spin-transfer-torque magnetic random access memory development. Here we provide a method to probe the heating of MTJ using the RKKY coupling of a synthetic ferrimagnetic storage layer as a thermal sensor. The temperature increase versus applied bias voltage is measured thanks to the decrease of the spin-flop field with temperature. This method allows distinguishing spin transfer torque (STT) effects from the influence of temperature on the switching field. The heating dynamics is then studied in real-time by probing the conductance variation due to spin-flop rotation during heating. This approach provides a new method for measuring fast heating in spintronic devices, particularly magnetic random access memory (MRAM) using thermally assisted or spin transfer torque writing.Index Terms -Spin transfer torque, Interlayer Exchange Coupling, Temperature measurement, heating dynamics.In MRAM, a current is sent through a magnetic tunnel junction (MTJ) to switch the storage layer magnetization by spin transfer torque (STT) [1][2][3], or in the plane of the bottom electrode if the storage layer magnetization is switched by spin orbit torque (SOT) [4][5][6]. In all cases, the readout is performed by measuring at low bias voltage (~0.2V) the resistance of the MTJ which differs in parallel and antiparallel magnetic configuration due to the tunnel magnetoresistance phenomenon (TMR). Depending on the current amplitude, pulse duration and MTJ resistance, the current can also increase the temperature because of the power dissipated in the line or in the junction [7][8][9]. Solutions to reduce the current flow and the associated power consumption are currently under investigation, in particular by using the voltage control of magnetic anisotropy [10]. The switching behavior of spin torque driven devices [11][12][13][14] is greatly influenced by a temperature increase, possibly larger than 100°C even during pulses in the nanosecond range. The temperature variations affect the magnetic parameters, such as magnetization, magnetocrystalline anisotropy, and change the thermal activation energy. If the relationship between MTJ temperature and current intensity is unknown, an additional free parameter must be adjusted to fit the experimental switching phase diagrams and derive the spin torque efficiency. This unknown T(V) relationship cannot be addressed by simply comparing the coercivity dependence with temperature to that created by Joule heating because in most cases the current necessary for heating is large enough to induce spin-torque that impacts the coercivity of the device, as later detailed in this paper. Therefore, it is important to know the relation between temperature and voltage by other means. As an example, this has been recently investigated using the spin-wave thermal population as a temperature probe [15].In Thermally Assisted MRAM (TA-MRAM) [7][8][9], the storage layer ...

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Thermally assisted MRAMs: ultimate scalability and logic functionalities

Cited by 103 publications

References 69 publications

Overview of emerging memristor families from resistive memristor to spintronic memristor

Overview of emerging memristor families from resistive memristor to spintronic memristor

Focused Kerr measurements on patterned arrays of exchange biased square dots

Steady State and Dynamics of Joule Heating in Magnetic Tunnel Junctions Observed via the Temperature Dependence of RKKY Coupling

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