scholarly journals Spin state of a single-molecule magnet (SMM) creating long-range ordering on ferromagnetic layers of a magnetic tunnel junction – a Monte Carlo study

RSC Advances ◽  
2021 ◽  
Vol 11 (51) ◽  
pp. 32275-32285
Author(s):  
Andrew Grizzle ◽  
Christopher D'Angelo ◽  
José Martínez-Lillo ◽  
Pawan Tyagi
Keyword(s):  
Single Molecule ◽  
Tunnel Junction ◽  
Room Temperature ◽  
Magnetic Tunnel Junction ◽  
Monte Carlo Study ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Ferromagnetic Electrodes ◽  
Ferromagnetic Layers ◽  
Long Range Ordering

Paramagnetic single-molecule magnets (SMMs) interacting with the ferromagnetic electrodes of a magnetic tunnel junction (MTJ) produce new molecular spintronics testbed and highly ordered magnetic metamaterial promising for room temperature.

scholarly journals Exploring room-temperature transport of single-molecule magnet-based molecular spintronics devices using the magnetic tunnel junction as a device platform

RSC Advances ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 13006-13015 ◽  
Author(s):  
Pawan Tyagi ◽  
Christopher Riso ◽  
Uzma Amir ◽  
Carlos Rojas-Dotti ◽  
Jose Martínez-Lillo
Keyword(s):  
Single Molecule ◽  
Tunnel Junction ◽  
Room Temperature ◽  
Magnetic Tunnel Junction ◽  
Single Molecule Magnet ◽  
Molecular Spintronics ◽  
Ferromagnetic Electrodes ◽  
Device Architecture

A device architecture utilizing a single-molecule magnet (SMM) as a device element between two ferromagnetic electrodes may open vast opportunities to create novel molecular spintronics devices.

Room Temperature Current Suppression on Magnetic Tunnel Junction Based Molecular Spintronics Devices

2013 ◽  
Vol 1507 ◽  
Author(s):  
Pawan Tyagi
Keyword(s):  
Tunnel Junction ◽  
Exchange Coupling ◽  
Room Temperature ◽  
Spin Transport ◽  
Magnetic Tunnel Junction ◽  
Test Bed ◽  
Force Microscopy ◽  
Molecular Spintronics ◽  
Ferromagnetic Electrodes ◽  
Strong Exchange

ABSTRACTMolecular conduction channels between two ferromagnetic electrodes can produce strong exchange coupling and dramatic effect on the spin transport, thus enabling the realization of novel logic and memory devices. To realize such device, we produced Multilayer Edge Molecular Spintronics Devices (MEMSDs) by bridging the organometallic molecular clusters (OMCs) across a ∼2 nm thick insulator of a magnetic tunnel junction (MTJ), along its exposed side edges. These MEMSDs exhibited unprecedented increase in exchange coupling between ferromagnetic films and dramatic changes in the spin transport. This paper focuses on the dramatic current suppression phenomenon exhibited by MEMSDs at room temperature. In the event of current suppression, the effective MEMESDs’ current reduced by as much as six orders in magnitude as compared to the leakage current level of a MTJ test bed. Current suppression phenomenon was found to be associated with the equally dramatic changes in the MTJ test beds due to OMCs. Role of OMC in changing MTJ test bed properties was determined by the three different types of magnetic characterizations: SQUID Magnetometer, Ferromagnetic Resonance, and Magnetic Force Microscopy. Observation of current suppression by independent research groups and supporting studies on similar systems will be crucially important to unequivocally establish the utility of MEMSD approach.

Correlating Blocking Temperatures in Single Molecule Magnets with Raman Relaxation

2018 ◽  
Author(s):  
Marcus J. Giansiracusa ◽  
Andreas Kostopoulos ◽  
George F. S. Whitehead ◽  
David Collison ◽  
Floriana Tuna ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Single Molecule ◽  
Energy Barrier ◽  
Thermal Relaxation ◽  
Relaxation Mechanism ◽  
Blocking Temperature ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Key Parameter

We report a six coordinate DyIII single-molecule magnet<br>(SMM) with an energy barrier of 1110 K for thermal relaxation of<br>magnetization. The sample shows no retention of magnetization<br>even at 2 K and this led us to find a good correlation between the<br>blocking temperature and the Raman relaxation regime for SMMs.<br>The key parameter is the relaxation time (𝜏<sub>switch</sub>) at the point where<br>the Raman relaxation mechanism becomes more important than<br>Orbach.

Room temperature spin valve effect in the NiFe/Gr–hBN/Co magnetic tunnel junction

2016 ◽  
Vol 4 (37) ◽  
pp. 8711-8715 ◽  
Author(s):  
Muhammad Zahir Iqbal ◽  
Salma Siddique ◽  
Ghulam Hussain ◽  
Muhammad Waqas Iqbal
Keyword(s):  
Boron Nitride ◽  
Tunnel Junction ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Spin Valve ◽  
Magnetic Tunnel Junction ◽  
Valve Effect ◽  
First Time

Graphene and hexagonal boron nitride (hBN) have shown fascinating features in spintronics due to their metallic and tunneling behaviors, respectively. In this work, we report for the first time room temperature spin valve effect in NiFe/Gr–hBN/Co configuration.

Recent advances in lanthanide coordination polymers and clusters with magnetocaloric effect or single-molecule magnet behavior

2021 ◽  
Author(s):  
Jun-Jie Hu ◽  
Yan Peng ◽  
Sui-Jun Liu ◽  
He-Rui Wen
Keyword(s):  
Quantum Computing ◽  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Coordination Polymers ◽  
Single Molecule ◽  
Information Storage ◽  
Lanthanide Ions ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Lanthanide Coordination Polymers

The molecular magnetorefrigerant materials for low-temperature magnetic refrigeration and single-molecule magnets for high-density information storage and quantum computing have received extensive attention from chemists and magnetic experts. Lanthanide ions with...

scholarly journals Structural Stability of Magnetic Tunnel Junction Based Molecular Spintronics Devices (MTJMSD)

2020 ◽  
Author(s):  
Joshua Dillard ◽  
Uzma Amir ◽  
Pawan Tyagi ◽  
Vincent Lamberti
Keyword(s):  
Thin Films ◽  
Structural Stability ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Molecular Devices ◽  
Metal Electrodes ◽  
Molecular Spintronics ◽  
Ferromagnetic Electrodes

Abstract Harnessing the exotic properties of molecular level nanostructures to produce novel sensors, metamaterials, and futuristic computer devices can be technologically transformative. In addition, connecting the molecular nanostructures to ferromagnetic electrodes bring the unprecedented opportunity of making spin property based molecular devices. We have demonstrated that magnetic tunnel junction based molecular spintronics device (MTJMSD) approach to address numerous technological hurdles that have been inhibiting this field for decades (P. Tyagi, J. Mater. Chem., Vol. 21, 4733). MTJMSD approach is based on producing a capacitor like a testbed where two metal electrodes are separated by an ultrathin insulator and subsequently bridging the molecule nanostructure across the insulator to transform a capacitor into a molecular device. Our prior work showed that MTJMSDs produced extremely intriguing phenomenon such as room temperature current suppression by six orders, spin photovoltaic effect, and evolution of new forms of magnetic metamaterials arising due to the interaction of the magnetic a molecule with two ferromagnetic thin films. However, making robust and reproducible electrical connections with exotic molecules with ferromagnetic electrodes is full of challenges and requires attention to MTJMSD structural stability. This paper focuses on MTJMSD stability by describing the overall fabrication protocol and the associated potential threat to reliability. MTJMSD is based on microfabrication methods such as (a) photolithography for patterning the ferromagnetic electrodes, (b) sputtering of metallic thin films and insulator, and (c) at the end electrochemical process for bridging the molecules between two ferromagnetic films separated by ∼ 2nm insulating gap. For the successful MTJMSD fabrication, the selection of ferromagnetic metal electrodes and thickness was found to be a deterministic factor in designing the photolithography, thin film deposition strategy, and molecular bridging process. We mainly used isotropic NiFe soft magnetic material and anisotropic Cobalt (Co) with significant magnetic hardness. We found Co was susceptible to chemical etching when directly exposed to photoresist developer and aged molecular solution. However, NiFe was very stable against the chemicals we used in the MTJMSD fabrication. As compared to NiFe, the Co films with &gt; 10nm thickness were susceptible to mechanical stress-induced nanoscale deformities. However, cobalt was essential to produce (a) low leakage current before transforming the capacitor from the magnetic tunnel junction into molecular devices and (b) tailoring the magnetic properties of the ferromagnetic electrodes. This paper describes our overall MTJMSD fabrication scheme and process optimization to overcome various challenges to produce stable and reliable MTJMSDs. We also discuss the role of mechanical stresses arising during the sputtering of the ultrathin insulator and how to overcome that challenge by optimizing the insulator growth process. This paper will benefit researchers striving to make nanoscale spintronics devices for solving grand challenges in developing advanced sensors, magnetic metamaterials, and computer devices.

Polyoxometalate-Supported Lanthanoid Single-Molecule Magnets

2014 ◽  
Vol 67 (11) ◽  
pp. 1542 ◽  
Author(s):  
Michele Vonci ◽  
Colette Boskovic
Keyword(s):  
Single Molecule ◽  
Energy Barrier ◽  
Magnetic Relaxation ◽  
Donor Ligands ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Coordination Numbers ◽  
Oxygen Donor ◽  
Slow Magnetic Relaxation

Polyoxometalates are robust and versatile multidentate oxygen-donor ligands, eminently suitable for coordination to trivalent lanthanoid ions. To date, 10 very different structural families of such complexes have been found to exhibit slow magnetic relaxation due to single-molecule magnet (SMM) behaviour associated with the lanthanoid ions. These families encompass complexes with between one and four of the later lanthanoid ions: Tb, Dy, Ho, Er, and Yb. The lanthanoid coordination numbers vary between six and eleven and a range of coordination geometries are evident. The highest energy barrier to magnetisation reversal measured to date for a lanthanoid–polyoxometalate SMM is Ueff/kB = 73 K for the heterodinuclear Dy–Eu compound (Bu4N)8H4[DyEu(OH)2(γ-SiW10O36)2].

Study of Anisotropy on Ferromagnetic Electrodes of a Magnetic Tunnel Junction-Based Molecular Spintronics Device (MTJMSD)

2021 ◽  
Author(s):  
Bishnu R. Dahal ◽  
Marzieh Savadkoohi ◽  
Eva Mutunga ◽  
Andrew Grizzle ◽  
Christopher D'Angelo ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Molecular Spintronics ◽  
Ferromagnetic Electrodes ◽  
Spintronics Device

Humidity driven molecular switch based on photoluminescent DyIIICoIII single-molecule magnets

2019 ◽  
Vol 7 (14) ◽  
pp. 4164-4172 ◽  
Author(s):  
Szymon Chorazy ◽  
Jakub J. Zakrzewski ◽  
Mateusz Reczyński ◽  
Koji Nakabayashi ◽  
Shin-ichi Ohkoshi ◽  
...  
Keyword(s):  
Single Molecule ◽  
Magnetic Relaxation ◽  
Room Temperature ◽  
Functional Materials ◽  
Molecular Switch ◽  
Dehydration Process ◽  
Single Molecule Magnets ◽  
Visible Photoluminescence ◽  
Slow Magnetic Relaxation

Functional materials incorporating cyanido-bridged DyIIICoIII molecules combine visible photoluminescence and slow magnetic relaxation, both switchable by the level of humidity within the reversible room temperature dehydration process.

Sign in / Sign up

Export Citation Format

Share Document