Search results “Ferromagnetic exchange coupling”
Magnetic Exchange Interaction
Subject:Physics Paper: Solid state theory
Views: 2034 Vidya-mitra
Mod-01 Lec-22 Exchange Interactions, Magnetic Order, Neutron Diffraction
Condensed Matter Physics by Prof. G. Rangarajan, Department of Physics, IIT Madras. For more details on NPTEL visit http://nptel.iitm.ac.in
Views: 14993 nptelhrd
Physics of Exchange Interactions in Solids
2010/5/30 Osaka,G-COE Physics of Exchange Interactions in Solids , T.Dietl , Polish Academy of Sciences , Warsaw University
Ferromagnetic Heisenberg Model
Subject:Physics Paper: Solid state theory
Views: 2337 Vidya-mitra
Solid State Magnetism (Lecture 7): Exchange Interaction
This video is part of a course taught by Dr. Sabieh Anwar at the Lahore University of Management Sciences (LUMS) in the Fall of 2016. The course deals with magnetism in the solid state. The course website is http://physlab.org/class-teaching/magnetism-2016 Welcome to the Khwarizmi Science Society Youtube Channel. The Khwarizmi Science Society (KSS) is a non-profit association aimed at furthering the science culture in Pakistan's educational insitiutions and in the general public.
Views: 3736 khwarizmisciencesoc
Magnetic exchange coupling part – i (CHE)
Subject : Chemistry Paper : Inorganic Chemistry-II Content writer :
Views: 3226 Vidya-mitra
Modeling anti-ferromagnetic coupling in a ferredoxin compound
Demonstration of setting up fragments within a molecule for modeling anti-ferromagnetic coupling (p.447).
Views: 468 Exploring Chemistry
Ferromagnetic Materials
We have discussed here what Ferromagnetic Materials is, in details along with its basic concept.
Views: 39105 Electrical4U
Enhanced magnetic properties in ZnCoAlO caused by exchange coupling to Co nanoparticles
Video abstract for the article ‘Enhanced magnetic properties in ZnCoAlO caused by exchange-coupling to Co nanoparticles‘ by Qi Feng, Wala Dizayee, Xiaoli Li, David S Score, James R Neal, Anthony J Behan, Abbas Mokhtari, Marzook S Alshammari, Mohammed S Al-Qahtani, Harry J Blythe (Qi Feng et al 2016 New J. Phys. 18 113040). Read the full article in New Journal of Physics http://iopscience.iop.org/article/10.1088/1367-2630/18/11/113040
Views: 116 NewJournalofPhysics
Exchange interaction
Exchange interaction In physics, the exchange interaction (with an exchange energy, and exchange term) is a quantum mechanical effect that only occurs between identical particles.Despite sometimes being called an exchange force in analogy to classical force, it is not a true force, as it lacks a force carrier. -Video is targeted to blind users Attribution: Article text available under CC-BY-SA image source in video https://www.youtube.com/watch?v=2N4cCIJZ328
Views: 4266 WikiAudio
Synthetic Anti-Ferromagnetic Nanostructures for Low Power Wearable Spintronic Devices
Developing compatible and energy‐efficient flexible spintronics is one of the key ingredients for wearable spintronic devices. E‐field controllable flexible spintronics provides a promising way, but remains unstudied. Here, based on ionic gel gating, the perpendicular Ruderman–Kittel–Kasuya–Yosida interaction and dynamic domain switching with an ultralow operation voltage in flexible synthetic anti‐ferromagnetic nanostructures are modulated. This is reported by Qu Yang, Ziyao Zhou, Liqian Wang, Hongjia Zhang, Yuxin Cheng, Zhongqiang Hu, Bin Peng, and Ming Liu in the article https://doi.org/10.1002/adma.201800449. To know more, please go to the Advanced Materials homepage.
Exchange Mechanisms in Macroscopically Ordered Organic Magnetic Semiconductors
Naveen Rawat Advisor: Madalina Furis Doctor of Philosophy Thesis Defense The origins of magnetic exchange mechanism between delocalized ligand electrons and spins in organic magnetic semiconductors has been of key interest as it underlies many complex optical and transport properties and is crucial for organic spintronics based devices. Better understanding of these exchange mechanisms is essential for tuning of magnetic exchange interaction to suit the need of practical magnetic and electronic devices. The interaction between magnetic ions in organic magnetic semiconductors is quite challenging to interpret due to competing exchange mechanisms present in crystalline thin films. Moreover, exploration of optical properties of thin films is challenging due to sub-micron grain sizes and the presence of numerous structural defects, disorder and large number of grain boundaries. However, this was overcome by synthesizing organo soluble phthalocyanine derivatives and fabricating macroscopically ordered semiconductor films by solution processing. Presence of fewer grain boundaries and defects while increasing the orbital overlap was essential in understanding the delocalization and diffusion length and its role in magnetic exchange mechanisms in these systems. Optical techniques such as linear dichroism, magnetic circular dichroism and magneto-pl are used and provide understanding about the relation between excitons, spin exchange mechanisms and collective magnetic behavior of delocalized electrons in organic semiconductors. An enhancement in the collective magnetization of the crystalline phthalocyanine thin films with strong exchange coupling between the delocalized ligand electrons and d-electrons is observed. The electronic states responsible for magnetic exchange are identified utilizing magnetic field and temperature dependent studies. Furthermore, soluble organics allow engineering of organic analogues to diluted magnetic semiconductors (DMS) by creation of metal/metal-free phthalocyanine alloys. Optical studies provided crucial information about delocalization and diffusion lengths in these systems allowing fine tuning of this delocalization length scale and metal-metal distance. The exploration of magnetic behavior in metal/metal-free Pc alloys opens an avenue for tuning magnetic properties and revealed an organic analogue to the RKKY type interaction. These studies will serve as a benchmark for probing magnetic exchange interactions in wide variety of organometallic crystalline thin films. This work was supported by the National Science Foundation, Division of Materials Research MRI, CAREER and EPM program awards: DMR- 0722451, DMR- 0821268, DMR-1307017 and DMR-1056589, DMR-1229217. A portion of this work was performed at the National High Magnetic Field Laboratory, Florida which is supported by the National Science Foundation through DMR-1157490.
Views: 274 PhysicsatUVM
Heisenberg model spin simulation
Phase transitions of a classical Heisenberg spin system depending on temperature T and magnetic field strength B (values indicated at the top left). "Proof of concept" test simulation. Open boundary conditions. Metropolis Algorithm. Spins interact via direct Heisenberg exchange and Dzyaloshinskii-Moriya interaction. At high temperature, the system is paramagnetic. At low temperature, the magnetic phase of the spin system depends on the magnetic field strength: 0 T - 3 T: Spin Spiral Phase 3 T - 8 T: Skyrmion Lattice Phase above 8 T: Ferromagnetic Phase
SFCM 18/19 10: Exchange Bias, the 2D magnetic interaction that is part of our modern life
SEMINARIOS INTERNACIONALES DE FRONTERAS DE LA CIENCIA DE MATERIALES Exchange Bias, the 2D magnetic interaction that is part of our modern life Jose Luis Prieto Instituto de Sistemas Optoelectrónicos y Microtecnología-ISOM Universidad Politécnica de Madrid, España Fecha del acto: 05/12/2018 Centro: E.T.S. DE ING. DE CAMINOS CANALES Y P. Entidad organizadora: CEI CAMPUS MONCLOA Descripción o resumen del acto: Exchange Bias is a surface interaction that couples an antiferromagnetic with a ferromagnetic material. The result is that the ferromagnetic material behaves as if there was an invisible external magnetic field applied in a given direction. This exchange interaction was discovered 60 years ago and went from being an oddity in the textbooks, to being a fundamentally important interaction that made the existence of modern reading heads in magnetic hard drives, possible. It made possible that the areal density in magnetic recording media doubled every year for more than a decade. In this talk we will begin by explaining the fundamental interactions in ferromagnetic materials and the things that one would or would not expect to see with a macroscopic magnet. Then, we will travel to the world of the magnetic surface interactions and in particular to Exchange Bias, and we will see that it can make the ferromagnet behave in funny ways that are not possible in the macroscopic world. By giving some notions of magnetic recording, we will see why Exchange Bias had such a big impact in our lives in the late 90’s. Finally, I will present some recent developments in this intensively investigated 60 years old interaction.
Views: 68 UPM
Tunable Kondo effect in double quantum dots coupled to ferromagnetic contacts
- By: Rosa Lopez, IFISC - Date: 2012-02-03 11:00:00 - Description: We investigate the transport properties of a serial double quantum dot when it is coupled to ferromagnetic contacts in the Kondo regime. The contact polarization generates effective magnetic fields and suppresses the Kondo effect in each dot. The super-exchange interaction (J), tuned by the inter-dot tunelling rate t, can be used to compensate the effective fields and restore the Kondo resonance when the contact polarizations are aligned. As a consequence, the direction of the spin conductance can be controlled and even reversed using electrostatic gates alone. Furthermore, we study the associated two-impurity Kondo model and show that a ferromagnetic exchange coupling (J) leads to an effective spin-1 exchange-anisotropic Kondo model which exhibits a quantum phase transition in the presence of partially polarized contacts.
Lecture39- Triplet States and the Exchange Interaction
Lecture39- How the anti-symmetry of a wavefunction leads to the exchange interaction, and why triplet states are lower in energy than singlets.
Mod-01 Lec-21 Quenching of Orbital Angular Momentum; Ferromagnetism
Condensed Matter Physics by Prof. G. Rangarajan, Department of Physics, IIT Madras. For more details on NPTEL visit http://nptel.iitm.ac.in
Views: 14783 nptelhrd
Theory of the Novel Mn-doped II-II-V Dilute Magnetic Semiconductors
The following is a pre-recorded version of my invited talk for the 2015 APS March Meeting in San Antonio, TX. My talk was in Session S31, and was delivered on March 5th, 2015 at 8:36 AM. The abstract for the talk can be found here: http://meeting.aps.org/Meeting/MAR15/Session/S31.4 The talk discusses the theory of the exciting new class of dilute magnetic semiconductors that are isostructural to a specific subset of iron-based superconductors. The materials are well suited to manipulation through doping, as magnetic and charge doping are handled in separate sublattices. The physics of these materials are transparent, and thus are suitable to theoretical analysis using density functional theory calculations. Using the material (Ba, K)(Zn, Mn)_2As_2, I explain in the talk how we performed and analyzed these calculations, and concluded that the magnetic interaction in this system is a combination of a superexchange interaction and an effective double exchange interaction. This implies that the magnetic interaction itself is tunable, and paves the way for increasing the system's Curie temperature. In addition, we also explain using a statistical model why, in experiment, the directly observed magnetization per Mn is strongly reduced from the 5 Bohr magnetons obtained from high-temperature susceptibility measurements. The talk is based on my Rapid Communication published in Physical Review B. The abstract for the paper is here: http://link.aps.org/doi/10.1103/PhysRevB.90.140403. If you do not have access to Physical Review B, a copy of the article can be downloaded from my personal website, http://jkglasbrenner.com, under the publications/papers section.
Views: 1658 James Glasbrenner
14. Physics | Magnetic Properties | Magnetization of Ferromagnetic Materials | by Ashish Arora
http://www.physicsgalaxy.com Learn complete Physics Video Lectures on Magnetic Properties of Materials for IIT JEE by Ashish Arora. This is the most comprehensive website on Physics covering all the topics in detail. No wonder, in its trial run itself, this one of its kind website topped the world ranking on Physics learning. To keep yourself updated about physics galaxy activities on regular basis follow the facebook page of physics galaxy at https://www.facebook.com/physicsgalaxy74 The website, aimed at nurturing grasping power students, has classroom lectures on almost all the topics. It is an outcome of 23-year long toil of Physics expert who has made it a mission to simplify the complexities of Physics. Ashish Arora, the brain behind this interactive unique website, has all his lectures available on web for free of cost. He has created a youtube channel in the name of Physics Galaxy. Today more than 6000 video lectures are being watched per day on this website which is highest among any other e-learning website in India. Till now more than 3.6 Million videos are watched on it. On each video subtitles are also available in 67 languages using google translator including English, Hindi, Chinese, French, Marathi, Bangla, Urdu and other regional and international languages. Besides uploading transcripts of all his videos, he has created a software based synchronized European voice accent of all videos to benefit students in USA, Europe and other countries. Reference link of this video is at http://youtu.be/Sz-gr2DCsFE
Views: 7572 Physics Galaxy
Coupling effect
Views: 582 Chemistry Channel
Exploring Magnetism with Ferromagnetic III-V Semiconductors
2010/5/30 Osaka,G-COE Exploring Magnetism with Ferromagnetic III-V Semiconductors , H.Ohno , Tohoku University
Double Exchange
Double Exchange
Views: 105 Myles Ing
Double-exchange mechanism Top # 7 Facts
Double-exchange mechanism Top # 7 Facts
Views: 690 AadharTwo1
Longitudinal domain wall formation in elongated assemblies of ferromagnetic nanoparticles
Longitudinal domain wall formation in elongated assemblies of ferromagnetic nanoparticles. Miriam Varón et al (2015), Scientific Reports http://dx.doi.org/10.1038/srep14536 Through evaporation of dense colloids of ferromagnetic ~13 nm ε-Co particles onto carbon substrates, anisotropic magnetic dipolar interactions can support formation of elongated particle structures with aggregate thicknesses of 100–400 nm and lengths of up to some hundred microns. Lorenz microscopy and electron holography reveal collective magnetic ordering in these structures. However, in contrast to continuous ferromagnetic thin films of comparable dimensions, domain walls appear preferentially as longitudinal, i.e., oriented parallel to the long axis of the nanoparticle assemblies. We explain this unusual domain structure as the result of dipolar interactions and shape anisotropy, in the absence of inter-particle exchange coupling.
Views: 158 ScienceVio
Exchange-spin model
Views: 117 coffeebeatlove
Multiferroics:Modelling and Understanding
2010/6/2 Osaka,G-COE Multiferroics:Modelling and Understanding , S.Picozzi , Consiglio Nazionale delle Ricerche Istituto SPIN
Origin of Ferromagnetism
Views: 3437 Sabaq. Pk
Spin crossover (CHE)
Subject: Chemistry Paper: Inorganic Chemistry-II Module: Spin crossover (CHE)
Views: 2267 Vidya-mitra
Single spin manipulation in quantum-dot spin valves
- By: Jan Martinek, Institute of Molecular Physics, Polish Academy of Sciences, Poznan, Poland - Date: 2010-09-22 15:00:00 - Description: We discuss the possibility to generate, manipulate, and probe single spins and their dynamics in single-level quantum dots (QDs) or single molecules coupled to ferromagnetic leads. We develop a theory of electron transport through QDs that are weakly coupled to ferromagnetic leads taking non-collinear magnetization of the leads into account, and allows for an externally-applied magnetic field. The spin-polarized current flowing between dot and electrodes leads to a non-equilibrium accumulation of spin on the dot. Both the magnitude and the direction of the dot\'s spin depend on the magnetic properties of leads and their coupling to the dot. They can be, furthermore, manipulated by either an externally applied magnetic field or an intrinsically present exchange field that arises due to the spin-polarized tunnel coupling of the strongly-interacting-QD states to ferromagnetic leads. The exchange field can be tuned by both the gate and bias voltage, which, therefore, provide convenient handles to manipulate the quantum-dot spin. Since the transmission through the QD spin valve sensitively depends on the state of the QD spin, all the dynamics of the latter is reflected in the transport properties of the device. We suggest a series of transport experiments on spin precession in QDs coupled to one or two ferromagnetic leads. An applied magnetic field gives rise to the Hanle effect. Recent experiments fit well to our predictions. We study also frequency-dependent current noise of this system. We show that the noise spectrum displays a resonance at the Larmor frequency, whose line-shape depends on the relative angle of the leads\' magnetizations. One can thus use the current noise as a tool to detect the electron spin resonance (ESR) from a single spin.
The Principle of Exchange
The importance of exchange in all human interactions; how application of this principle increases personal and societal well-being. On a personal level, exchange in the classroom and in relationships; the Five Love Languages cited to illustrate different 'media' of exchange.
Views: 836 TheWyvern66
Exchange Bias in Co/Pt multilayers simulation/experiment comparison
The upper left panel represents the simulated domain dynamics in a Co/Pt ferromagnetic film coupled to a Cobalt oxide antiferromagnet underneath as an external magnetic field is increased up the saturation value. The other panels represent magnetic force microscopy images taken on a real sample at different magnetic field values. The domain retraction promoted by the external field is biased by the coupling with the antiferromagnet. Putting the experimentally measured antiferromagnet field in the domain equation of motion we observe a good quantitative agreement between simulated and measured domain dynamics. This kind of modeling allows to unravel the intimate microscopic details leading to exchange bias in thin disordered ferro/antiferro interfaces. Want to know more? Visit https://sites.google.com/site/benassia/home
Views: 621 Andrea Benassi
Matlab Micromagnetics Animations
These micromagnetic simulations are done in MATLAB. Each rotating vector represents an individual nanoparticle under the macrospin approximation. These simulations attempt to see if treating individual particles in a collection as spins in a typical micromagnetic discretization scheme yields realistic results. Time-domain measurements of these types of dynamics is the focus of my dissertation work at the University of South Carolina. Geeky Details: The interaction fields in the simulation are: Heisenberg exchange, anisotropy, Zeeman, and the demagnetizing field. The effective field is found by the functional derivative of these energies. The demagnetizing field is found by Fourier transform. This is because a general demagnetizing field is found by a convolution of the magnetization matrix and the demagnetizing tensor, which reduces to a simple product in the Fourier domain. Then an inverse Fourier transform is taken to reveal the magnetic field. The exchange constant for magnetite, A, is 7pJ/m (the value shown in the text above the animation is a scaled version from the code). The exchange interaction here is over a 7-point Laplacian stencil considering only the 6 nearest neighbors. Note how the increasing particle distance causes the magnetic reversal to become less and less coherent. This is due to the short distance over which the exchange interaction is dominant. As the distance increases, the long-range dipolar fields are dominant and the vectors are thus less inclined to remain parallel. This work is an extension of a previous work of Ru Zhu. I thank him for his advice to me on the simulation of non-rectangular geometries (not shown here). This work extends the former by adapting it to CPUs (rather than GPUs), going to a 3-D model space, animating the simulation, and various other outputs not shown in the video. Download the code to this type of simulation here: http://www.egenriether.com/code.html
Views: 323 egenriether
Magnetic domain dynamics - 3
Observing magnetic domains in ferromagnetic thin films
Views: 90 Hadi AlQahtani
Superexchange Meaning
Video shows what superexchange means. An interaction of the electrons of two molecular entities mediated by one or more molecules or ions.. Superexchange Meaning. How to pronounce, definition audio dictionary. How to say superexchange. Powered by MaryTTS, Wiktionary
Views: 818 ADictionary
STEAM Exchanges: Bias - Pamela Salsberry
Pamela Salsberry, a professor in the College of Public Health at The Ohio State University, discusses how bias affects health in this STEAM Exchange talk.
Views: 75 The STEAM Factory
Dynamically stabilized magnetic skyrmions
Dynamically stabilized magnetic skyrmions. Y. Zhou et al (2015), Nature Communications http://dx.doi.org/10.1038/ncomms9193 Magnetic skyrmions are topologically non-trivial spin textures that manifest themselves as quasiparticles in ferromagnetic thin films or noncentrosymmetric bulk materials. So far attention has focused on skyrmions stabilized either by the Dzyaloshinskii–Moriya interaction (DMI) or by dipolar interaction, where in the latter case the excitations are known as bubble skyrmions. Here we demonstrate the existence of a dynamically stabilized skyrmion, which exists even when dipolar interactions and DMI are absent. We establish how such dynamic skyrmions can be nucleated, sustained and manipulated in an effectively lossless medium under a nanocontact. As quasiparticles, they can be transported between two nanocontacts in a nanowire, even in complete absence of DMI. Conversely, in the presence of DMI, we observe that the dynamical skyrmion experiences strong breathing. All of this points towards a wide range of skyrmion manipulation, which can be studied in a much wider class of materials than considered so far.
Views: 510 ScienceVio
Shell Ferromagnetism
Antiferromagnetic Heusler alloys exhibit unidirectional shell-ferromagnetic properties when decomposed under a magnetic field. See article for more.. http://www.nature.com/articles/srep28931
Views: 458 asli cakir
Nonlinear Dynamics of Hisenberg Ferromagnetic spin chain
Nonlinear Dynamics of Hisenberg Ferromagnetic spin chain by Prof. Lakshmanan
Views: 184 matsciencechannel
material studioTutorial 2: Carbon based Magnetism
Publishcation: "Correlation between charge transfer and exchange coupling in carbon-based magnetic materials" http://dx.doi.org/10.1063/1.4933076 - Ligand-Driven Exchange Coupling in Graphene-Based Magnetic Materials http://doi.org/10.2320/matertrans.M2016092
Views: 61 Thanh-FIBO FX
Double Exchange
Views: 71 Bryce Priester
Magnetic domains in an iron core
This video looks at why magnetism passes so readily through iron. It is designed to compliment the "How transformers work" video. The video looks at what domains are, why magnetism permeates through iron so readily and the behaviour of domains in an alternating magnetic field. This video is aimed at UK GCSE students (age 15-16).
Views: 38508 t33chin

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