arXiv subjects

Brandon Zink

Publications and source records attributed to Brandon Zink.

3 recordsLinked to original sources

arXiv2025

Demonstration of Electron-Mediated Voltage-Controlled Exchange Coupling in Perpendicular Magnetic Tunnel Junctions

Electron-mediated voltage control of exchange coupling (EM-VCEC) has been proposed as a mechanism for magnetization switching via modulation of spin-dependent electron reflection. However, its experimental verification has been challenging due to the coexistence of slower, voltage-induced ionic effects. Here, we fabricate magnetic tunnel junction (MTJ) devices that enable nanosecond timescale voltage application. Our results reveal rapid exchange coupling modulation on the nanosecond timescale, consistent with an electronic origin. The observed enhancement and saturation at low temperatures further rule out ionic migration, conclusively confirming the electronic nature of the mechanism. These results establish EM-VCEC as a viable mechanism for fast and energy-efficient voltage-driven magnetic switching.

physics.app-ph↗

arXiv2024

Energy Efficient Stochastic Signal Manipulation in Superparamagnetic Tunnel Junctions via Voltage-Controlled Exchange Coupling

Superparamagnetic tunnel junctions (sMTJs) are emerging as promising components for stochastic units in neuromorphic computing, owing to their tunable random switching behavior. Conventional MTJ control methods, such as spin-transfer torque (STT) and spin-orbit torque (SOT), often require substantial power. Here, we introduce the voltage-controlled exchange coupling (VCEC) mechanism, enabling switching between antiparallel and parallel states in sMTJs with an ultralow power consumption of only 40 nW, approximately two orders of magnitude lower than conventional STT-based sMTJs. This mechanism yields a sigmoid-shaped output response, making it ideally suited for neuromorphic computing applications. Furthermore, we validate the feasibility of integrating VCEC with the SOT current control, offering an additional dimension for magnetic state manipulation. This work marks the first practical demonstration of VCEC effect in sMTJs, highlighting its potential as a low-power control solution for probabilistic bits in advanced computing systems.

physics.app-ph↗

arXiv2022

On Error Correction for Nonvolatile Processing-In-Memory

Processing in memory (PiM) represents a promising computing paradigm to enhance performance of numerous data-intensive applications. Variants performing computing directly in emerging nonvolatile memories can deliver very high energy efficiency. PiM architectures directly inherit the vulnerabilities of the underlying memory substrates, but they also are subject to errors due to the computation in place. Numerous well-established error correcting codes (ECC) for memory exist, and are also considered in the PiM context, however, they typically ignore errors that occur throughout computation. In this paper we revisit the error correction design space for nonvolatile PiM, considering both storage/memory and computation-induced errors, surveying several self-checking and homomorphic approaches. We propose several solutions and analyze their complex performance-area-coverage trade-off, using three representative nonvolatile PiM technologies. All of these solutions guarantee single error correction for both, bulk bitwise computations and ordinary memory/storage errors.

cs.ET↗