Magnetism of Ultrathin Fe Films in the Vicinity of Transition from Ferromagnetism to Superparamagnetism

2006 ◽  
Vol 512 ◽  
pp. 165-170
Author(s):  
Yu Shiratsuchi ◽  
Yasushi Endo ◽  
Masahiko Yamamoto
Keyword(s):  
Magnetic Anisotropy ◽  
Growth Temperature ◽  
Magnetic State ◽  
Ferromagnetic State ◽  
Film Structure ◽  
Dominant Factor ◽  
Magnetic Anisotropy Energy ◽  
Flat Substrate ◽  
Effective Magnetic Anisotropy ◽  
Superparamagnetic State

We have investigated the magnetism of ultrathin Fe films grown on the inclined Al2O3(0001), especially, in the vicinity of ferromagnetic-superparamagnetic transition. In the transition region, the magnetic state of Fe films is the coexistence of ferromagnetism and superparamagnetism. The ratio of the components in ferromagnetic and superparamagnetic state is dependent on the growth temperature. For Fe grown on the flat substrate without the inclination, as the growth temperature increases, the ratio of the component in ferromagnetic state increases, reaches to the maximum and decreases again. On the presence of substrate inclination, the ratio of the component in ferromagnetic state increases, reaches to the maximum and decreases again. decreases monotonically with increasing growth temperature. We investigated the dominant factor of the complex magnetic state, and clarified that the complex magnetic state is dominated by the change of the film structure and the effective magnetic anisotropy energy.

Correlation Between Elastic Constants and Magnetic Anisotropy in Co/Pt Superlattice Thin Films

2005 ◽  
Vol 875 ◽  
Author(s):  
Nobutomo Nakamura ◽  
Hirotsugu Ogi ◽  
Teruo Ono ◽  
Masahiko Hirao ◽  
Takeshi Yasui ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Anisotropy ◽  
Layer Thickness ◽  
Elastic Constants ◽  
Elastic Strain Energy ◽  
Anisotropy Energy ◽  
Magnetic Anisotropy Energy ◽  
Magnetoelastic Anisotropy ◽  
Anisotropy Effect ◽  
Effective Magnetic Anisotropy

AbstractIn this paper, we study contribution of the magnetoelastic anisotropy effect on perpendicular magnetic anisotropy of Co/Pt superlattice thin films. The effective-magnetic anisotropy energy was measured for Co/Pt thin films with a constant Co-layer thickness (4 Å) deposited on silicon substrate by the ultrahigh-vacuum deposition method. As the Pt-layer thickness increases, the effective-magnetic anisotropy energy increases and decreases after showing a maximum at the Pt-layer thickness of 12 Å. This behavior can be explained only by the magnetoelastic anisotropy effect, that is, elastic-strain energy released through the magnetostriction effect with the strain-dependent elastic constants.

scholarly journals Spin-reversal energy barriers of 305 K for Fe2+ d6 ions with linear ligand coordination

Nanoscale ◽  
2017 ◽  
Vol 9 (30) ◽  
pp. 10596-10600 ◽  
Author(s):  
Lei Xu ◽  
Ziba Zangeneh ◽  
Ravi Yadav ◽  
Stanislav Avdoshenko ◽  
Jeroen van den Brink ◽  
...  
Keyword(s):  
Solid State ◽  
Magnetic Anisotropy ◽  
Point Group ◽  
Group Symmetry ◽  
Point Group Symmetry ◽  
State Matrix ◽  
Magnetic Anisotropy Energy ◽  
Spin Reversal ◽  
Ligand Coordination ◽  
Li Ion

A remarkably large magnetic anisotropy energy of 305 K is computed by quantum chemistry methods for divalent Fe2+ d6 substitutes at Li-ion sites with D6h point-group symmetry within the solid-state matrix of Li3N.

Magnetic anisotropy energy of antiferromagnetic coupled Fe/Cr/Fe layers (abstract)

1991 ◽  
Vol 69 (8) ◽  
pp. 5321-5321
Author(s):  
C. M. Williams ◽  
J. J. Krebs ◽  
G. A. Prinz ◽  
A. Chaiken
Keyword(s):  
Magnetic Anisotropy ◽  
Anisotropy Energy ◽  
Magnetic Anisotropy Energy

Exchange Bias in CrO2/Cr2O3 Bilayer Thin Films

2006 ◽  
Vol 45 ◽  
pp. 2528-2533 ◽  
Author(s):  
S. Srinath ◽  
N.A. Frey ◽  
H. Srikanth ◽  
G.X. Miao ◽  
A. Gupta
Keyword(s):  
Thin Films ◽  
Magnetic Anisotropy ◽  
Variable Thickness ◽  
Exchange Bias ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Anisotropy Constant ◽  
Effective Magnetic Anisotropy ◽  
Large Anisotropy

We have investigated the exchange bias in CVD grown epitaxial CrO2/Cr2O3 bilayer thin films using hysteresis loops and resonant RF transverse susceptibility. M-H loops indicated an enhanced coercivity without appreciable loop shift and the transverse susceptibility in CrO2/Cr2O3 bilayers revealed features associated with both the ferromagnetic and antiferromagnetic phases. In addition, TS yielded large anisotropy constant (Keff) values depending on the fraction of Cr2O3 present. The large anisotropy fields observed cannot be accounted for by the variable thickness of CrO2 alone and are indicative of possible exchange coupling between CrO2 and Cr2O3 phases that significantly affects the effective magnetic anisotropy.

Orbital angular momentum-driven anomalous Hall effect

2021 ◽  
Author(s):  
Oliver Dowinton ◽  
Mohammad Bahramy
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Transition Metal Oxides ◽  
Magnetic State ◽  
Magnetic Moments ◽  
Anomalous Hall Effect ◽  
Ferromagnetic State ◽  
Periodic Systems ◽  
Spin States ◽  
Berry Curvature

Abstract Orbital angular momentum (OAM) plays a central role in regulating the magnetic state of electrons in non-periodic systems such as atoms and molecules. In solids, on the other hand, OAM is usually quenched by the crystal field, and thus, has a negligible effect on magnetisation. Accordingly, it is generally neglected in discussions around band topology such as Berry curvature (BC) and intrinsic anomalous Hall conductivity (AHC). Here, we present a theoretical framework demonstrating that crystalline OAM can be directionally unquenched in transition metal oxides via energetic proximity of the conducting d electrons to the local magnetic moments. We show that this leads to `composite' Fermi-pockets with topologically non-trivial OAM textures. This enables a giant Berry curvature with an intrinsic non-monotonic AHC, even in collinearly-ordered spin states. We use this model to explain the origin of the giant AHC observed in the forced-ferromagnetic state of EuTiO3 and propose it as a prototype for OAM driven AHC.

Comparison between Magnetic Anisotropy Energy and a Parameter to the Assessment of Magnetic Property of Electrical Steel

2018 ◽  
Vol 930 ◽  
pp. 449-453
Author(s):  
R.A.C. Felix ◽  
R.L.O. da Rosa ◽  
Luiz P. Brandão
Keyword(s):  
Magnetic Properties ◽  
Magnetic Property ◽  
Magnetic Anisotropy ◽  
Electrical Steel ◽  
Anisotropy Energy ◽  
Alternative Methods ◽  
Magnetic Polarization ◽  
Magnetic Anisotropy Energy ◽  
Electrical Steels ◽  
Global Parameters

Alternative methods of quantitative texture analysis are applied to characterize the non-oriented grain electrical steels (NOG) in relation to their magnetic properties. Magnetic anisotropy energy (Ea) and A parameter are two models based on crystallographic texture that generates global parameters that can be used to predict the magnetic properties of NOG steels. In this work, these two models were used to evaluate the magnetic polarization and compared between themselves to realize which one best correlates to this property.

scholarly journals Calculation of magnetic anisotropy energy inSmCo5

2003 ◽  
Vol 67 (21) ◽  
Author(s):  
P. Larson ◽  
I. I. Mazin ◽  
D. A. Papaconstantopoulos
Keyword(s):  
Magnetic Anisotropy ◽  
Anisotropy Energy ◽  
Magnetic Anisotropy Energy
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