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Prosenjit Das

Publications and source records attributed to Prosenjit Das.

10 recordsLinked to original sources
arXiv2025

Exploring the Role of Interfacial Dzyaloshinskii-Moriya Interaction in Write Error Rate Anomalies of Spin-Transfer Torque Magnetic Tunnel Junctions

The performance and reliability of spin-transfer torque magnetic random-access memory (STT-MRAM) can be compromised by anomalous switching behavior, especially during high-speed operations. One such anomaly, known as the "ballooning effect" is characterized by an unexpected non-monotonic increase in the write error rate (WER) with increase in STT current at specific current pulse durations. In this study, we systematically investigate the role of the interfacial Dzyaloshinskii-Moriya interaction (DMI) on such WER anomaly using micromagnetic simulations of 20 nm and 50 nm magnetic tunnel junctions (MTJs). We show that DMI promotes incoherent magnetization reversal, prolongs the switching time and creates intermediate multidomain states that result in incomplete reversal. At high DMI values, these states persist even under large switching current densities, reproducing ballooning-like anomalies reported experimentally. In contrast, longer pulses overcome these effects by allowing the system sufficient time to reach a stable state. Our findings show that interfacial DMI can play a role in the ballooning effect and point to interfacial engineering as a practical strategy for improving the reliability of next-generation STT-MRAM.

cond-mat.mes-hall↗
arXiv2022

Rank and rigidity of locally nilpotent derivations of affine fibrations

In this exposition, we propose a notion of rank and rigidity of locally nilpotent derivations of affine fibrations. We show that the concept is analogous to the perception of rank and rigidity of locally nilpotent derivations of polynomial algebras. Our results characterize locally nilpotent derivations of $\mathbb{A}^3$-fibrations having slice by classifying the fixed point free locally nilpotent derivations in terms of their ranks.

math.AC↗
arXiv2020

A Note on Residual Variables of an Affine Fibration

In a recent paper [El 13], M.E. Kahoui has shown that if $R$ is a polynomial ring over $\mathbb{C}$, $A$ an $\mathbb{A}^3$-fibration over $R$, and $W$ a residual variable of $A$ then $A$ is stably polynomial over $R[W]$. In this article we show that the above result holds over any Noetherian domain $R$ provided the module of differentials $\Omega_R(A)$ of the affine fibration $A$ (which is necessarily a projective $A$-module by a theorem of Asanuma) is a stably free $A$-module.

math.AC↗
arXiv2020

On cancellation of variables of the form $bT^n-a$ over affine normal domains

In this article we extend a cancellation theorem of D. Wright to the case of affine normal domains. We shall show that if $A$ is an algebra over a Noetherian normal domain $R$ containing a field $k$ and if $A[T ] = R^{[3]}$, then $A = R^{[2]}$ if and only if $A[T]$ has a variable of the form $bT^n - a$ for some $a, b \in A$ with $n \ge 2$ and $ch(k) \nmid n$.

math.AC↗
arXiv2020

Planes of the form $b(X,Y)Z^n-a(X,Y)$ over a DVR

In this paper we extend an epimorphism theorem of D. Wright to the case of discrete valuation rings. We will show that if $(R, t)$ is a discrete valuation ring, $n \ge 2$ is an integer not divisible by the characteristic of the residue field $R/tR$, and $g \in R[X, Y, Z]$ is a polynomial of the form $g = b(X,Y)Z^n - a(X,Y)$ such that $R[X, Y, Z]/(g)$ is a polynomial algebra in two variables, then $g$ and $Z$ form a pair of variables in $R[X, Y, Z]$. We will also show that the result holds over any Noetherian domain containing $\mathbb{Q}$.

math.AC↗