In superparamagnetic tunnel junctions (SMTJ), the energy barriers that separate the parallel and the antiparallel magnetization configurations are sufficiently small that the thermal noise causes stochastic magnetization fluctuations between the two states. Through magnetoresistance effects, those stochastic fluctuations give rise to telegraphic noise signals with two voltage levels (see Fig.1) [1, 2]. The relative average time spent in each of the two configurations can be controlled by an applied dc current via the spin-transfer torque. Due to their inherent stochastic nature, SMTJs are promising candidates for truly random number generator applications [3, 4], brain-inspired and probabilistic computing [5-10]. However, an external bias magnetic field was always required to fully operate the SMTJ’s with current, which represents a drawback to their integration with the required microelectronic circuits. In this work, we report for the first time, SMTJs that are fully controlled by DC current at zero applied magnetic field using perpendicular magnetic tunnel junctions (pMTJ). Stable pMTJs are used in densely magnetic memories [11], nevertheless their thermal stability can be strongly reduced by tuning their free layer thickness, leading to a superparamagnetic state. Here, we use pMTJ’s with a free layer thickness of t=1.6 nm, and with diameters ranging from 150 nm to 80 nm. By applying a DC current in one direction (sign), without any external bias field, we observe stochastic fluctuations in the resistance for dc currents between -0.3 mA and -0.27 mA. As shown in Fig. 2, the average probability in being in high and low resistance state is well controlled by the applied current. In order to obtain good statistics on the extracted probability, we record to stochastic transitions. We extracted the dwell time distribution, which follows an exponential distribution with a mean dwell time that is in agreement with the modified Néel-Brown model. The authors acknowledge partial funding from ERC MAGICAL No 669204, and the Nanoscience Foundation (Grenoble, France).

![](https://assets.underline.io/uploads/markdown_image/1/image/032d011551d8698e3dc1b74244af9c81.jpg)

Figure 1 : Experimental voltage time trace of the SMTJ.

![](https://assets.underline.io/uploads/markdown_image/1/image/f8c0fe8daabe77b0c738c5d388eadce3.jpg)

Figure 2 : The probability of occupancy of the high resistance state versus current.

Current controlled perpendicular superparamagnetic tunnel junctions operating at zero applied magnetic field

Spin-transfer torque (STT) based magnetoresistive random-access memory (MRAM) is of great current interest for embedded applications, due to its high speed, high endurance, and long retention time. However, state-of-the-art STT MRAM requires a large switching current that leads to reliability issues, high write energy, and limits the density scaling. In this talk, we will show that a conventional current-controlled MTJ can be changed to a voltage-controlled device if we replace the thin oxide barrier with a resonant tunneling barrier. Such a simple modification will combine two established quantum phenomena: interlayer exchange coupling and resonant tunneling within the scaled magnetic structure to enable a resonant-exchange controlled (REC) magnetization switching [1]. REC-driven magnetization switching can substantially lower the write energy, decouple the energy and speed of operations, eliminate the reliability issues, and enable denser MRAM technologies. A voltage-controlled MTJ has a high baseline resistance, which may cause compatibility issues with standard CMOS. We will discuss a magnetic gain cell structure that consists of a REC MTJ and two transistors for a large separation in the output current for the two memory states while retaining the low power advantages of a voltage-controlled write mechanism [2]. We analyze the REC MTJ using quantum-transport simulations on a CoFeB/MgO/Ru/MgO/CoFeB structure and combine the results with an empirical SPICE model to analyze the magnetic gain cell using 45 nm CMOS models in HSPICE. Our simulation results suggest approximately 103 times change in the read current in the gain cell between the two magnetic states. The expected energy and delay are 29.5 fJ/bit and 1.6 ns respectively for a write operation and 7.6 ~ 39 fJ/bit and 0.6 ~ 1 ns respectively for a read operation, thus promising for low energy, fast, and high-density REC MRAM technology.

![](https://assets.underline.io/uploads/markdown_image/1/image/8f55c819fa0feacf6498620a60124061.jpg)

A magnetic gain-cell structure for efficient voltage-controlled MRAM

Voltage control of magnetism provides a promising path toward the development of low-power spintronic devices. Magneto-ionics exploiting voltage-driven ion migration as a control mechanism has attracted interest because it can generate large magnetoelectric effects at low voltage. Here, we demonstrate the use of all-solid-state lithium-ion battery technology for reversible voltage-controlled switching between perpendicular and in-plane magnetization states in a Co/Pt bilayer. The magneto-ionic battery structure consists of a 2 nm Ta/5 nm Pt/20 nm LiCoO2/70 nm LiPON/3 nm Co/5 nm Pt crossbar junction (Fig. 1a,b). Here, the LiPON film functions as a solid-state electrolyte and the LiCoO2 acts as the Li+ storage layer. Using magneto-optical Kerr effect (MOKE) microscopy, we show that the magnetization of the Co film switches between in-plane and perpendicular directions when voltages of +2.5 V and –2 V are applied (Fig. 1c,d). The magneto-ionic switching effect is reliably reproduced over multiple cycles (Fig. 2a,b) and switching takes less than 0.5 s at room temperature (Fig. 2c). Our structure can be cycled for &gt;500 times without degradation. The magnetoelectric coupling efficiency is estimated to be 7,700 fJ/Vm at room temperature, which is the strongest magnetoelectric effect reported to date. We attribute the effect to changes in the hybridization of electron orbitals at the Co/Pt interface upon voltage-controlled insertion and deinsertion of Li+ ions. Our work sets a new benchmark for lithium-based magneto-ionics and demonstrates the relevance of battery design principles for the development of low-power spintronic devices.

![](https://assets.underline.io/uploads/markdown_image/1/image/0e0e0a222892a8e22e21ad864ff48d48.jpg)

Fig. 1 (a) Schematic of the magneto-ionic battery structure. (b) Optical microscopy image of a single crossbar junction. (c) Polar and (d) longitudinal MOKE hystersis curves recorded at –2.0 and +2.5 V.

![](https://assets.underline.io/uploads/markdown_image/1/image/7f80d4c4edc9f54a6a38f9541a3f553c.jpg)

Fig. 2 Reversible voltage-controlled switching of (a) the perpendicular magnetization and (b) the in-plane magnetization in zero magnetic field. (c) Time-resolved modulation of the longitudinal MOKE signal at room temperature recorded while toggling the voltage between –2.0 V and +2.5V in 0.5 s intervals.

Lithium-Ion Battery Technology for Voltage Control of Perpendicular Magnetization

Magnetoionics (MI) is a much-in-demand feature for spintronics devices due to its great potential for improving energy efficiency in memory devices. The main feature of MI is to allow for the nonvolatile modulation of magnetic properties [1–5], making MI reversibility a fundamental quality for high device performance. Various studies have addressed issues impacting reversibility such as the presence of different types of ions, oxides and the degree of oxidation at the oxide/ferromagnetic interface [3, 5–8], while the influence of annealing temperature on reversibility has been largely overlooked. Annealing is commonly used to induce crystallization in CoFeB layers leading to the enhancement of perpendicular magnetic anisotropy (PMA), interfacial Dzyaloshinskii-Moriya interaction (iDMI), and tunnel magnetoresistance [9–11], therefore its impact on MI is of great interest. In this study, we show that W/CoFeB/HfO2 thin films annealed at 350°C and 390°C show a significant but irreversible dependence of PMA and DMI on gate voltage. However, an annealing program using a slow ramp that minimizes the exposure to the highest temperatures allows to induce PMA and iDMI while also showing a MI reversibility of 71% in remanence with respect to PMA. This dependence of MI reversibility on annealing profiles and temperatures could be related to the different degrees of crystallinity obtained under different annealing conditions. Such structural differences, such as size and distribution of crystallites, can greatly impact the ion mobility inside the stack and be responsible for observed modulation of the MI reversibility. Our results therefore show that annealing parameters need to be optimized to obtain enhanced magnetic properties without compromising MI performance.

![](https://assets.underline.io/uploads/markdown_image/1/image/54d50bab8c546ddbc8fd33ecfea28690.jpg)

![](https://assets.underline.io/uploads/markdown_image/1/image/bf6e6dbd3a0f9277642eaa6aab5dd034.jpg)

Effect of Annealing on Magnetoionics in W/CoFeB/HfO2

Effect of Annealing on Magnetoionics in W/CoFeB/HfO2

Examing Microagressions to Promote Diversity in Speech-Language Pathology
Speech-language pathologists serve clients from diverse backgrounds and strive to honor cultural and linguistic diversity. Microaggressions, representing systemic biases within society, appear across settings and affect minoritized individuals. This session will provide clinicians with a framework for identifying types of microaggressions, their impact, and ways to promote inclusion.


Learning Objectives:
-Describe types of microaggressions and their connection to societal biases for minoritized individuals and communities.
-Identify examples of microaggressions within speech-language pathology, and explain their effects in clinical, educational, and research settings.
-Examine and address individual and environmental microaggressions within their own work settings to promote diversity.

Examing Microagressions to Promote Diversity in Speech-Language Pathology

Lo studio delle patologie del linguaggio, unito alle più moderne tecniche di indagine, costituisce una risorsa importante per ampliare le nostre conoscenze sui processi neurocognitivi dell'elaborazione linguistica, sui circuiti e le aree anatomiche che governano la manifestazione del linguaggio. Questa consapevolezza, sporadicamente presente nella storia della linguistica, si è consolidata in tempi recenti portando a progressi significativi nella descrizione dei diversi malfunzionamenti linguistici, consentendo l'arricchimento delle nostre conoscenze sulla facoltà del linguaggio e favorendo lo sviluppo di test diagnostici più mirati e sofisticati.
Il filone di ricerca incentrato sull’analisi dei comportamenti linguistici cosiddetti ‘disturbati’ presenta inoltre una forte componente intrinsecamente interdisciplinare: numerose sono, infatti, le competenze scientifiche necessarie per far luce, sotto diverse angolazioni, su questa complessa tematica. La prospettiva di studio più promettente dovrebbe, pertanto, orientarsi innanzi tutto verso la costruzione di un dialogo sinergico, a più voci, tra i diversi ambiti che possono partecipare allo studio del pathological speech. Più in particolare il recente, notevole incremento degli studi delle patologie del linguaggio, grazie al sostegno di nuove metodologie di raccolta e analisi di dati che hanno avuto un'importante ricaduta anche sulla costruzione degli obiettivi stessi delle indagini, porta a valorizzare un approccio non solo crossdisciplinare, aperto a più discipline operanti in autonomia, ma anche interdisciplinare, nell'ottica quindi di una maggiore cooperazione tra le discipline.
Attualmente gli studi in questa direzione rappresentano una risorsa preziosa di dati e di spunti di riflessione, utili per una migliore valutazione selettiva delle componenti biologiche, genetiche, cognitive, ma anche ambientali e sociali che entrano in gioco nel processo globale di acquisizione e/o di perdita di una lingua. Restano tuttavia ancora molti aspetti, sia teorici sia metodologici, che è opportuno approfondire e per i quali risulta necessario disporre di più ampie e accessibili raccolte di dati relative alle produzioni linguistiche patologiche, che possano costituire una base empirica adatta a favorire nuovi protocolli di validazione diagnostica e di intervento terapeutico. Studi recenti hanno mostrato, ad esempio, la rilevanza delle competenze del linguista ai fini di diagnosi precoci di diverse patologie attraverso l'individuazione di specifici predittori di deficit linguistico. Questo workshop è dedicato alla presentazione di risorse linguistiche che abbiano l’obiettivo di documentare il parlato patologico nelle sue diverse manifestazioni (afasia, morbo di Parkinson, schizofrenia, balbuzie, DSL, DSA, sordità etc.) e alle numerose aree di studio che, in un’ottica multisciplinare, si occupano dell’interazione tra linguaggio e patologie. Saranno privilegiati contributi che si pongano, anche metodologicamente, il problema dell'approccio multidisciplinare al tema delle patologie del linguaggio e che presentino corpora e/o analisi di dati su più livelli descrittivi. Obiettivo prioritario sarà il confronto tra patologia e normofasia nelle sue varie declinazioni e livelli di analisi (fonetico/fonologico, morfologico, sintattico, lessicale, prosodico e pragmatico).

Underline digital video library

Current controlled perpendicular superparamagnetic tunnel junctions operating at zero applied magnetic field

A magnetic gain-cell structure for efficient voltage-controlled MRAM

Lithium-Ion Battery Technology for Voltage Control of Perpendicular Magnetization

Effect of Annealing on Magnetoionics in W/CoFeB/HfO2

Examing Microagressions to Promote Diversity in Speech-Language Pathology

C-ORAL-ESQ: A spoken corpus of spontaneous speech by Brazilian schizophrenic patients

New Insights into the Pathophysiology of Primary Aldosteronism

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