scholarly journals The role of ultrafast magnon generation in the magnetization dynamics of rare-earth metals

2020 ◽  
Vol 6 (39) ◽  
pp. eabb1601 ◽  
Author(s):  
B. Frietsch ◽  
A. Donges ◽  
R. Carley ◽  
M. Teichmann ◽  
J. Bowlan ◽  
...  
Keyword(s):  
Rare Earth ◽  
Spin Dynamics ◽  
Magnetic Moments ◽  
Rare Earth Metals ◽  
Ultrafast Dynamics ◽  
Magnetization Dynamics ◽  
Time Resolved ◽  
Spin Lattice ◽  
Dynamics Simulations

Ultrafast demagnetization of rare-earth metals is distinct from that of 3d ferromagnets, as rare-earth magnetism is dominated by localized 4f electrons that cannot be directly excited by an optical laser pulse. Their demagnetization must involve excitation of magnons, driven either through exchange coupling between the 5d6s-itinerant and 4f-localized electrons or by coupling of 4f spins to lattice excitations. Here, we disentangle the ultrafast dynamics of 5d6s and 4f magnetic moments in terbium metal by time-resolved photoemission spectroscopy. We show that the demagnetization time of the Tb 4f magnetic moments of 400 fs is set by 4f spin–lattice coupling. This is experimentally evidenced by a comparison to ferromagnetic gadolinium and supported by orbital-resolved spin dynamics simulations. Our findings establish coupling of the 4f spins to the lattice via the orbital momentum as an essential mechanism driving magnetization dynamics via ultrafast magnon generation in technically relevant materials with strong magnetic anisotropy.

scholarly journals The role of spin-lattice coupling for ultrafast changes of the magnetic order in rare earth metals

2021 ◽  
Vol 119 (18) ◽  
pp. 182404
Author(s):  
Beatrice Andres ◽  
Sang Eun Lee ◽  
Martin Weinelt
Keyword(s):  
Rare Earth ◽  
Magnetic Order ◽  
Rare Earth Metals ◽  
Spin Lattice ◽  
Lattice Coupling

scholarly journals Role of vacancies, light elements and rare-earth metals doping in CeO2

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
H. Shi ◽  
T. Hussain ◽  
R. Ahuja ◽  
T. W. Kang ◽  
W. Luo
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Light Elements

Outlook on Magnetization Dynamics

2017 ◽  
Author(s):  
Olle Eriksson ◽  
Anders Bergman ◽  
Lars Bergqvist ◽  
Johan Hellsvik
Keyword(s):  
First Principles ◽  
Spin Dynamics ◽  
Dynamic Processes ◽  
Original Formulation ◽  
Magnetization Dynamics ◽  
Switching Dynamics ◽  
Theoretical Investigations ◽  
Ultrafast Switching ◽  
Dynamics Simulations

Since its original formulation in the mid-1990's, atomistic spin-dynamics has become an important tool for modelling of dynamic processes in magnetic materials. So far this book has described current methodological methods and functionalities of atomistic spin-dynamics simulations. Applications of DFT and ASD techniques to selected topics have been presented in this book, for instance methods for calculation of the microscopic Heisenberg and Gilbert parameter from first principles (Chapters 2 and 6), multiscale modelling of magnon spectra in bulk and thin film magnets (Chapter 9), and theoretical investigations of ultrafast switching dynamics in ferromagnets and ferrimagnets (Chapter 10), and of exotic dynamics of topologically protected spin textures (Chapter 11). In this closing chapter we give an outlook on recent and anticipated developments of the methodology.

7. For all practical purposes: technologies of the elements

2004 ◽  
pp. 139-157
Author(s):  
Philip Ball
Keyword(s):  
Eighteenth Century ◽  
Rare Earth ◽  
Rare Earth Metals ◽  
Steel Production ◽  
Cold Fusion ◽  
Platinum Group Metals ◽  
Iron And Steel ◽  
Semiconducting Properties ◽  
Computer Chips

‘For all practical purposes: technologies of the elements’ considers the variety that exists within the elements, and how they can be applied to our everyday lives. Iron and steel gave early armies the edge in battle, but the role of carbon in steel production was not understood until the eighteenth century. Silicon was used in glass for centuries, but its semiconducting properties make it the ideal substance for computer chips. The platinum group metals were unsuccessfully marketed as alternatives to silver, but now they are integral in catalytic converters. Palladium gained notoriety as a key ingredient of ‘cold fusion’, and rare earth metals are used in television screens.

Effects of Ce on the Inclusions and Mechanical Properties of 2Cr13 Stainless Steel

2012 ◽  
Vol 174-177 ◽  
pp. 1344-1348
Author(s):  
Xiao Liu ◽  
Long Mei Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Rare Earth ◽  
Impact Toughness ◽  
Rare Earth Metals ◽  
Transverse Impact ◽  
Metallographic Examination ◽  
Dimple Fracture ◽  
Reduction Of Area

The effects of rare earth metals on the inclusions and the mechanical properties of 2Cr13 stainless steel were studied by metallographic examination, scanning electron microscope (SEM) and energy spectrum analysis. The results show that the morphologies and sizes of inclusions in 2Cr13 stainless steel are changed, and rare earth metals played a very good role of modifying inclusions. The fracture mode of 2Cr13 stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding Ce into the steel, and the spherical inclusions of rare earth oxysulfide in the dimple are the main factors for this transformation. The transverse impact toughness of 2Cr13 stainless steel is improved obviously by Ce. In comparison with 2Cr13 stainless steel without Ce, the transverse impact toughness of 2Cr13 stainless steel with Ce is increased 54.55% at -40°C, and the room temperature strength are improved, the elongation and reduction of area have been improved 11.90%, 16.67 respectively.

scholarly journals Ultrafast and Distinct Spin Dynamics in Magnetic Alloys

SPIN ◽  
2015 ◽  
Vol 05 (03) ◽  
pp. 1550004 ◽  
Author(s):  
I. Radu ◽  
C. Stamm ◽  
A. Eschenlohr ◽  
F. Radu ◽  
R. Abrudan ◽  
...  
Keyword(s):  
Exchange Interaction ◽  
Data Storage ◽  
Magnetic Circular Dichroism ◽  
Dynamic Properties ◽  
Spin Dynamics ◽  
Magnetic Moments ◽  
Dynamical Behavior ◽  
Laser Pulses ◽  
Time Resolved ◽  
Fs Laser

Controlling magnetic order on ultrashort timescales is crucial for engineering the next-generation magnetic devices that combine ultrafast data processing with ultrahigh-density data storage. An appealing scenario in this context is the use of femtosecond (fs) laser pulses as an ultrafast, external stimulus to fully set the orientation and the magnetization magnitude of a spin ensemble. Achieving such control on ultrashort timescales, e.g., comparable to the excitation event itself, remains however a challenge due to the lack of understanding the dynamical behavior of the key parameters governing magnetism: The elemental magnetic moments and the exchange interaction. Here, we investigate the fs laser-induced spin dynamics in a variety of multi-component alloys and reveal a dissimilar dynamics of the constituent magnetic moments on ultrashort timescales. Moreover, we show that such distinct dynamics is a general phenomenon that can be exploited to engineer new magnetic media with tailor-made, optimized dynamic properties. Using phenomenological considerations, atomistic modeling and time-resolved X-ray magnetic circular dichroism (XMCD), we demonstrate demagnetization of the constituent sub-lattices on significantly different timescales that depend on their magnetic moments and the sign of the exchange interaction. These results can be used as a “recipe” for manipulation and control of magnetization dynamics in a large class of magnetic materials.

Indirect Exchange Coupling of Magnetic Moments in Rare-Earth Metals

1971 ◽  
Vol 3 (3) ◽  
pp. 1025-1033 ◽  
Author(s):  
Lawrence Baylor Robinson ◽  
Lloyd N. Ferguson ◽  
Frederick Milstein
Keyword(s):  
Rare Earth ◽  
Exchange Coupling ◽  
Magnetic Moments ◽  
Rare Earth Metals ◽  
Indirect Exchange
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