Blar i NTNU Open på forfatter "Qaiumzadeh, Alireza"
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All-optical Magnetisation Switching in Two-dimensional Metallic Ferro- and Antiferromagnetic Systems
Krogen, Andreas Sandø (Master thesis, 2018)Motivated by recent experimental and theoretical work on ultrafast optical switching of magnetic order in ferromagnetic and antiferromagnetic materials, we study the influence of polarised light on the spin polarisation ... -
An antiferromagnetic and insulating leaky integrate-and-fire neuron and its application
Austefjord, Johannes Wiger (Master thesis, 2022)Ettersom størrelsen på transistorer begynner å tilsvare utstrekningen til et par atomer, blir det stadig vanskeligere å holde tritt med Moore's lov. Samtidig forskes det på nye metoder for mer energieffektiv maskinvare. ... -
Anisotropies and magnetic phase transitions in insulating antiferromagnets determined by a Spin-Hall magnetoresistance probe
Lebrun, Romain; Ross, Andrew; Gomonay, Olena; Bender, Scott A.; Baldrati, Lorenzo; Kronast, Florian; Qaiumzadeh, Alireza; Sinova, Jairo; Brataas, Arne; Duine, Rembert; Klaui, Mathias Michael (Journal article; Peer reviewed, 2019)Antiferromagnets possess a number of intriguing and promising properties for electronic devices, which include a vanishing net magnetic moment and thus insensitivity to large magnetic fields and characteristic terahertz ... -
Anomalous Thermoelectric Effect in Tilted Dirac and Weyl Semimetals
Ballestad, Thorvald Molthe (Master thesis, 2022)Effektive Dirac likninger i topologisk faststoff-fysikk kan, i motsetning til høy-energi ekvivalentene, ha ledd som ikke er Lorentz invariante. Flere slike systemer har blitt oppdaget, både teoretisk og eksperimentelt, ... -
Antiferromagnetic Neuromorphic Computing
Tønseth, Even Aksnes (Master thesis, 2022)Nevromorf prosessering er et felt innen datavitenskap som har som mål å designe prosseseringsenheter med inspirasjon fra hjernedynamikk. Når en lager slike prosessorer med tradisjonell halvleder teknologi møter en store ... -
Bose–Einstein condensation of nonequilibrium magnons in confined systems
Mohseni, Morteza; Qaiumzadeh, Alireza; Serga, Alexander; Brataas, Arne; Hillebrands, Burkard; Pirro, Philipp (Peer reviewed; Journal article, 2020)We study the formation of a room temperature magnon Bose–Einstein condensate (BEC) in nanoscopic systems and demonstrate that its lifetime is influenced by the spatial confinement. We predict how dipolar interactions and ... -
Chiral ferromagnetism beyond Lifshitz invariants
Ado, I. A.; Qaiumzadeh, Alireza; Brataas, Arne; Titov, M. (Peer reviewed; Journal article, 2020)We consider a contribution w ch to the micromagnetic energy density that is linear with respect to the first spatial derivatives of the local magnetization direction. For a generalized two-dimensional Rashba ferromagnet, ... -
Control of magnetic states and spin interactions in bilayer CrCl3 with strain and electric fields: an ab initio study
Ebrahimian, Ali; Dyrdał, Anna; Qaiumzadeh, Alireza (Peer reviewed; Journal article, 2023)Using ab initio density functional theory, we demonstrated the possibility of controlling the magnetic ground-state properties of bilayer CrCl3 by means of mechanical strains and electric fields. In principle, we investigated ... -
Current-Driven Dynamics of Magnetic Hopfions
Wang, Xiansi; Qaiumzadeh, Alireza; Brataas, Arne (Journal article; Peer reviewed, 2019)opological magnetic textures have attracted considerable interest since they exhibit new properties and might be useful in information technology. Magnetic hopfions are three-dimensional (3D) spatial variations in the ... -
Ferromagnetic Nano-Oscillators for Neuromorphic computing
Hågensen, Frida (Master thesis, 2024)Det er en pågående revolusjon innen kunstig intelligens. Bare i løpet av de siste årene har implementasjonen av nevrale nettverk og maskinlæring eksplodert. Som følge av økende krav til energiforbruk, lagring og ... -
Impact of inherent energy barrier on spin-orbit torques in magnetic-metal/semimetal heterojunctions
Gao, Tenghua; Qaiumzadeh, Alireza; Troncoso, Roberto E.; Haku, Satoshi; An, Hongyu; Nakayama, Hiroki; Tazaki, Yuya; Zhang, Song; Tu, Rong; Asami, Akio; Brataas, Arne; Ando, Kazuya (Peer reviewed; Journal article, 2023)Spintronic devices are based on heterojunctions of two materials with different magnetic and electronic properties. Although an energy barrier is naturally formed even at the interface of metallic heterojunctions, its ... -
Long-distance spin-transport across the Morin phase transition up to room temperature in ultra-low damping single crystals of the antiferromagnet α-Fe2O3
Lebrun, Romain; Ross, Andrew; Gomonay, Olena; Baltz, V.; Ebels, U; Barra, Anne Laure; Qaiumzadeh, Alireza; Brataas, Arne; Sinova, Jairo; Klaui, Mathias Michael (Peer reviewed; Journal article, 2020)Antiferromagnetic materials can host spin-waves with polarizations ranging from circular to linear depending on their magnetic anisotropies. Until now, only easy-axis anisotropy antiferromagnets with circularly polarized ... -
Magnetodynamic properties of dipole-coupled 1D magnonic crystals
Singh, Suraj Kumar; Wang, Xiansi; Kumar, Ankit; Qaiumzadeh, Alireza; Svedlindh, Peter; Tybell, Per Thomas Martin; Wahlström, Erik (Journal article, 2021)Magnonic crystals are magnetic metamaterials, that provide a promising way to manipulate magnetodynamic properties by controlling the geometry of the patterned structures. Here, we study the magnetodynamic properties of ... -
Magnon Condensation of Magnetic Insulators
Kristoffersen, Anne Louise (Master thesis, 2023)Bose-Einstein kondensasjon er et forskningsfelt som har fått økt oppmerksomhet etter at Ketterle et al. og Cornell et al., i 1995, fremstilte et kondensat for første gang. Begge gruppene laget kondensatet av reelle ... -
Micromagnetic study of spin transport in easy-plane antiferromagnetic insulators
Brehm, Verena Johanna; Gomonay, Olena; Lepadatu, Serban; Klaüi, Mathias; Sinova, Jairo; Brataas, Arne; Qaiumzadeh, Alireza (Journal article; Peer reviewed, 2023) -
Nernst effect in 2D graphene layers
Leraand, Kristoffer (Master thesis, 2024)Dirac og Weyl semimetaller er materialer med spennende egenskaper og lavenergi eksitasjoner som oppfører seg som relativistiske Dirac fermioner. Det har blitt vist at tredimensjonale Weyl semimetaller er vertskap til en ... -
Neuromorphic computing with ferromagnetic nano-oscillators
Lyngaas, Jens Anker (Master thesis, 2023)I løpet av de siste ̊arene har nevrale nettverk blitt fremtredende gjennom maskin- læring. Disse er ofte implementert p ̊a kommersielt tilgjengelige, transistorbaserte enheter, som ikke er godt egnet til ̊a etterligne ... -
Nonequilibrium magnons from hot electrons in antiferromagnetic systems
Barbeau, Marion; Titov, Mikhail; Katsnelson, Mikhail I.; Qaiumzadeh, Alireza (Peer reviewed; Journal article, 2023)We describe a \emph{nonthermal} magnon activation mechanism in antiferromagnetic (AFM) systems via locally equilibrated \emph{spin-unpolarized} hot electrons excited by an ultrafast intense laser pulse. We employ a quantum ... -
Numerical Investigation of Quantum Scattering Problems - The Lippmann-Schwinger Equation and the Dynamical Formulation of Time-Independent Scattering
Eckle, Håkon Kvitvik (Master thesis, 2024)I denne avhandlingen studerer vi kvantespredning i to dimensjoner, både ved hjelp av standardmetoden med Lippmann-Schwinger-ligningen og den nye dynamiske formuleringen av tidsuavhengig spredning. Vi utvikler et numerisk ... -
Optical Conductivity of Dirac Fermions in Antiferromagnetic Semimetals
Ottesen, Herman Lileng (Master thesis, 2021)