arXiv subjects

Aditya Raj

Publications and source records attributed to Aditya Raj.

5 recordsLinked to original sources

arXiv2026

Room-Temperature Electric-Field Control of Anomalous Hall Effect in Py/BTO/LSMO Heterostructures

We demonstrate room temperature electric field control of the anomalous Hall effect in epitaxial Ni80Fe20 (Py) BaTiO3 (BTO) La0.7Sr0.3MnO3 (LSMO) thin film heterostructures grown on MgO and LaAlO3 substrates. Substrate induced strain states generate distinct magnetic anisotropies, enabling voltage driven tuning between anomalous and topological Hall contributions. Robust ferroelectric polarization in BTO, confirmed by piezoresponse force microscopy, couples strongly to interfacial orbital reconstruction and carrier redistribution. As a result, Hall resistivity exhibits giant low voltage tunability, with up to nearly 93 percent modulation at operating voltages of only 0.5 tand 2 V. Density functional theory calculations further reveal polarization controlled Rashba spin splitting, establishing a direct link between ferroelectric order and emergent quantum transport. These findings establish Py/BTO/LSMO heterostructures as promising candidates for low-power multifunctional spintronic devices, where substrate engineering enables control over emergent quantum transport phenomena.

cond-mat.mtrl-sci↗

arXiv2025

State-of-the-art Small Language Coder Model: Mify-Coder

We present Mify-Coder, a 2.5B-parameter code model trained on 4.2T tokens using a compute-optimal strategy built on the Mify-2.5B foundation model. Mify-Coder achieves comparable accuracy and safety while significantly outperforming much larger baseline models on standard coding and function-calling benchmarks, demonstrating that compact models can match frontier-grade models in code generation and agent-driven workflows. Our training pipeline combines high-quality curated sources with synthetic data generated through agentically designed prompts, refined iteratively using enterprise-grade evaluation datasets. LLM-based quality filtering further enhances data density, enabling frugal yet effective training. Through disciplined exploration of CPT-SFT objectives, data mixtures, and sampling dynamics, we deliver frontier-grade code intelligence within a single continuous training trajectory. Empirical evidence shows that principled data and compute discipline allow smaller models to achieve competitive accuracy, efficiency, and safety compliance. Quantized variants of Mify-Coder enable deployment on standard desktop environments without requiring specialized hardware.

cs.SE↗

arXiv2025

Radiogenomic Bipartite Graph Representation Learning for Alzheimer's Disease Detection

Imaging and genomic data offer distinct and rich features, and their integration can unveil new insights into the complex landscape of diseases. In this study, we present a novel approach utilizing radiogenomic data including structural MRI images and gene expression data, for Alzheimer's disease detection. Our framework introduces a novel heterogeneous bipartite graph representation learning featuring two distinct node types: genes and images. The network can effectively classify Alzheimer's disease (AD) into three distinct stages:AD, Mild Cognitive Impairment (MCI), and Cognitive Normal (CN) classes, utilizing a small dataset. Additionally, it identified which genes play a significant role in each of these classification groups. We evaluate the performance of our approach using metrics including classification accuracy, recall, precision, and F1 score. The proposed technique holds potential for extending to radiogenomic-based classification to other diseases.

cs.LG↗

arXiv2019

Investigation of nitrogen polar p-type doped GaN/AlxGa(1-x)N superlattices for applications in wide-bandgap p-type field effect transistors

In this study the MOCVD growth and electrical properties of N-polar modulation doped p-AlGaN/GaN superlattices (SLs) were investigated. Hole sheet charge density and mobility were studied as a function of the concentration of the p-type dopant Mg in the SL and the number of SL periods. Room temperature Hall measurements were carried out to determine the hole mobility and the sheet charge density. While the hole density increased with increasing number of SL periods, the hole mobility was largely unaffected.Hole mobilities as high as 18cm2/Vs at a simultaneous high hole density of 6.5e13 cm-2 were observed for N-polar SLs with a Mg modulation doping of 7.5e18 cm-3. For comparable uniformly doped Ga-polar SL samples, a mobility of 11cm2/Vs was measured. Lowest sheet resistance in the GaN/AlGaN materials system of 5kOhm/sq is also reported. Test-structure transistors were also fabricated to investigate the applicability of these SL structures, with planar device resulting in a current of 5mA/mm, and a FinFET structure resulting in a current of over 100mA/mm.

physics.app-ph↗

arXiv2019

AlGaN /GaN superlattice based p-channel field effect transistor (pFET) with TMAH treatment

To realize the full spectrum of advantages that the III-nitride materials system offers, the demonstration of p-channel III-nitride based devices is valuable. Authors report the first p-type field effect transistor (pFET) based on an AlGaN/GaN superlattice (SL), grown using MOCVD. Magnesium was used as the p-type dopant. A sheet resistance of 11.6 kΩ/sq, and a contact resistance of 14.9Ω.mm was determined using transmission line measurements (TLM) for a Mg doping of 1.5e19cm^-3 of Mg. Mobilities in the range of 7-10 cm\^2/Vs and a total sheet charge density in the range of 1e13-6e13 cm-2 were measured using room temperature Hall effect measurements. Without Tetramethylammonium hydroxide (TMAH) treatment, the fabricated pFETs had a maximum drain-source current (IDS) of 3mA/mm and an On-Resistance (RON) of 3.48 kΩ.mm, and did not turn-off completely. With TMAH treatment during fabrication, a maximum IDS of 4.5mA/mm, RON of 2.2kΩ.mm, and five orders of current modulation was demonstrated, which is the highest achieved for a p-type transistor based on (Al,Ga)N.

physics.app-ph↗