Magnetic Materials and Device Physics laboratory

Contact: surya at phy dot iith dot ac dot in

The Magnetic Materials and Device Physics Laboratory (MMDP) at IIT Hyderabad is driven by the motivation to advance both fundamental science and technological innovation in the fields of magnetism, spintronics, and nanoscale device physics. The laboratory seeks to unravel the underlying physics of magnetic materials and quantum transport phenomena while simultaneously translating these insights into practical devices such as memristors, spintronic components, and neuromorphic architectures. By integrating materials discovery, nanotechnology, and quantum engineering, the lab aims to contribute to next-generation computing, energy-efficient electronics, and quantum technologies. Equally important, it serves as a training ground for young researchers, fostering interdisciplinary collaboration and equipping them with the skills to address global challenges in data storage, artificial intelligence hardware, and sustainable energy solutions. In essence, the laboratory’s motivation lies in bridging fundamental physics with real-world applications, thereby positioning IIT Hyderabad as a hub for cutting-edge research and innovation in advanced materials and devices.

Quantum phenomena - conductance quantization - memory

Magnesium oxide (MgO) is important for the memory devices primarily in magnetic tunnel junctions (MTJs) for magnetic random-access memory (MRAM) devices. Here we report on the multibit memory characteristics, conductance quantization and shape of the nanogap at the nano-constriction in an Ag/MgO/FTO memristor device. Quantum Point Contact (QPC) analysis reveals a wide nanogap at the nano-constriction, supported by an energy-barrier aspect ratio of tB/R ≈ 0.1947. The device exhibits stable bipolar switching with a window of ~100, governed by space-charge-limited conduction in the high-resistance state (HRS) and Ohmic transport in the low-resistance state (LRS). During RESET, controlled filament rupture produces clear integer and half-integer conductance quanta (G0), enabling robust 4-bit (18 levels) quantized states. Pulse-programming measurements further demonstrate ~6.5-bit (92 levels) current states. These results elucidate atomic-scale filament evolution in MgO and highlight its promise for precision multilevel memory and neuromorphic computing applications.

Journal Ref: Advanced Functional Materials, 0:e77009 (2026)

Spintronics - Memory devices

6-bit memory devices with different magnetization states are of great interest since they can encode six bits of information per memory cell and cater a 64-fold increase in data storage capability compared to single-bit systems that can significantly boost data density and computational efficiency. Here, present our findings of 64 distinct magnetization states (6-bit) by varying applied voltages, revealing the potential for 6-bit data storage capabilities in Ag/α-Fe₂O₃/Fe/FTO based devices. These magnetization states are volatile in nature. Large vertical magnetization shifts of hysteresis loop in Ag/α-Fe₂O₃/Fe/FTO device is evident when electric field EZ applied magnetic field BZ are parallel. Observed vertical magnetization shift is calculated to be 44 emu/cc (79%) for the applied voltage of 3 V. This substantial change is attributed to the pinning of spins at the interface due to resistive switching phenomenon induced by oxygen ion migration across the interface. The resistive switching behavior exhibits non-volatile behaviour with analog bipolar resistive switching characteristics observed for approximately 95 cycles. Reversible and reproducible magnetization switching is demonstrated by repeatedly applying 0.2 V and 1.2 V, underscoring the robustness of the switching behaviour in the fabricated device. Magnetization shift changes with change in voltage and it enhances as the applied voltage increases. This type of capabilities offers significant potential for advancing multi-bit data storage and enhancing the efficiency of spintronic devices.

Journal ref: Applied Physics A 130 (10), 767 (2024)

Optical memristors and neuromorphic computing

Memristor-based optoelectronic artificial synapses have a high potential to enhance the efficiency of future neuromorphic computing. Like neurons of the retina, they have the potential to enable real-time visual pre-processing. This highlights the growing importance of improving optoelectronic artificial synapses for next-generation neuromorphic computing and neuromorphic visual systems. These artificial synapses can enhance neuromorphic visual systems, extending their capabilities beyond visible light. This study introduces a P-type copper oxide-based optical memristor device that exhibits fundamental bio-synaptic characteristics, which can be tuned using optical stimuli. We also demonstrated light-induced short-term plasticity and optical paired-pulse facilitation, which are the two important characteristics of neurons of the human retina that help in image pre-processing. We also implemented Pavlovian conditioning on the device using a combination of electrical and optical stimuli. These results indicate the possibility of using this device as an optically controlled artificial synaptic device for neuromorphic vision sensor applications.

Journal Ref: ACS Applied Electronic Materials 7, 4, 1622–1631 (2025)

Magnetronic memristors - Neuromorphic computing

Neuromorphic devices and their technologies have emerged as a novel approach to meet the growing demands of data – intensive applications. It offers substantially higher energy efficiency compared to traditional computers which work based on von Neumann architecture. In this respect, tuning synaptic characteristics like long-term potentiation (LTP) and long-term depression (LTD) by external stimuli in a remote way can be an alternative energy efficient approach. Hence, we report on our efforts in manifesting remote control of neuromorphic functionalities in α-Fe2O3 based synaptic device using magnetic field. For this work, we used spintronic based material and fabricated Ag/α-Fe2O3/FTO synaptic device. By the application of magnetic field strength ⁓ 80 Oe, a significant change in LTP and LTD characteristics are evidenced. The change in conductance of the device with magnetic field is attributed to Lorentz force and spin dependent scattering. We believe that modulation of LTP and LTD in a remote way would indeed pave a new approach in developing neuromorphic technologies. Apart from that we also demonstrated Pavlov’s classical conditioning which is an associative learning mechanism in the biological brain.

Journal Ref: Physica status solidi a 222, e202500314 (2025)

Heusler alloy thin films for spintronic applications

Journal Ref:

Physica B: Condensed Matter, 418912 (2026)
Journal of Magnetism and Magnetic Materials 620, 172910 (2025)

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