Shape-induced bi-stable magnetic states in submicrometer structures of permalloy films

Spin-orbit torques emerge as a promising method for manipulating magnetic configurations of spintronic devices. Here, we show that these torques can induce a magnetization reversal via domain wall propagation which may open new ways in developing novel spintronic devices and in particular in realizing high-density multi-level magnetic memory. Our devices are bi-layer heterostructures of Ni0.8Fe0.2 on top of β-Ta patterned in the form of two or three crossing ellipses which exhibit in the crossing area shape-induced biaxial and triaxial magnetic anisotropy, respectively. We demonstrate field-free switching between discrete remanent magnetic states of the structures by spin-orbit torques induced by flowing electrical current through one of the ellipses. We note switchings induced by the coupling between the ellipses where current flowing in one ellipse triggers a reversal in a neighboring ellipse which propagates from the center outwards. Numerical tools successfully simulate the observed coupling-induced switching using experimentally extracted parameters.

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“…A comprehensive study of magnetic behavior of structures such as Device 1 and Device 2 were presented in ref. 31,33–35 respectively.…”

Section: Resultsmentioning

confidence: 99%

Switching of multi-state magnetic structures via domain wall propagation triggered by spin-orbit torques

Das

Zaig

Nhalil

et al. 2019

Sci Rep

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“…2(d) shows very sharp switchings between the different remanent states. Please note that a comprehensive study of the magnetic properties of structures such as Device 3 is presented in refs 38 , 39 . Additional magnetic characterization is presented in the supplementary material.…”

Section: Resultsmentioning

confidence: 99%

Magnetization switching of multi-state magnetic structures with current-induced torques

Das

Avraham

Telepinsky

et al. 2018

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Spintronic devices often require the ability to locally change the magnetic configuration of ferromagnetic structures on a sub-micron scale. A promising route for achieving this goal is the use of heavy metal/ferromagnetic heterostructures where current flowing through the heavy metal layer generates field-like and anti-damping like torques on the magnetic layer. Commonly, such torques are used to switch magnets with a uniaxial anisotropy between two uniformly magnetized states. Here, we use such torques to switch magnetization in Ta/Ni0.80Fe0.20 heterostructures with uniaxial and biaxial anisotropy, where in the latter the magnetization is non-uniform. The anisotropies are induced by shape and the magnetic state is monitored using the planar Hall effect. As structures with several easy axes induced by shape can be part of a magnetic memory element, the results pave the way for multi-level magnetic memory with spin-orbit torque switching.

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“…1. The memory is constructed out of a single layer of magnetic material, as was previously presented in [3][4]. The readout operation of the memory is initiated by conducting a current between points A and B of the structure.…”

Section: Phe-mram Structure and Requirementsmentioning

confidence: 99%

“…However, this isn't the only memory technology to take advantage of the magnetic properties of materials. One such type of magnetic memory technology is the Planar-Hall-Effect (PHE) MRAM [3][4]. This type of memory is based on the PHE in magnetic films, and its single-layer structure makes it simpler to manufacture when compared with the MTJ structure.…”

Section: Introductionmentioning

confidence: 99%

Analog readout circuit for zero leakage Planar-Hall-Effect-Magnetic-Random-Access-Memory

Mordakhay

Fish

2014

2014 IEEE Faible Tension Faible Consommation

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An analog readout circuit for use in conjunction with the Planar-Hall-Effect Magnetic-Random-Access-Memory is presented. The non-volatile nature of this type of memory allows zero leakage during memory retention, allowing significant power saving. The circuit employs a novel technique for readout operation of memory bit-cells. The circuit uses chopping and switched-capacitor techniques for amplification of the low input signal as well as elimination of DC-offset and low-frequency noise. The binary nature of the data allows an area efficient implementation at the cost of linearity, which is less significant for memory readout applications. The proposed circuit was implemented in the TowerJazz 180nm CMOS process at a supply voltage of 1.8V, and can reliably sense input signals with amplitude of as low as 1mV.

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Shape-induced bi-stable magnetic states in submicrometer structures of permalloy films

Cited by 12 publications

References 11 publications

Switching of multi-state magnetic structures via domain wall propagation triggered by spin-orbit torques

Switching of multi-state magnetic structures via domain wall propagation triggered by spin-orbit torques

Magnetization switching of multi-state magnetic structures with current-induced torques

Analog readout circuit for zero leakage Planar-Hall-Effect-Magnetic-Random-Access-Memory

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