Theoretical Study of the Magnetic Anisotropy of Ni Films on Cu(001)

1997 ◽  
Vol 475 ◽  
Author(s):  
M. Freyss ◽  
R. Lorenz ◽  
H. Dreysse ◽  
J. Hafner
Keyword(s):  
Magnetic Anisotropy ◽  
Theoretical Study ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Real Space ◽  
Spin Orbit Coupling ◽  
Magnetization Direction ◽  
Out Of Plane ◽  
Lmto Method ◽  
The Stability

ABSTRACTThe anisotropy properties of Ni films on Cu(001) are quite unusual compared to other systems: The magnetization direction of Ni is in-plane for a coverage smaller than a critical thickness of 7 monolayers and out-of-plane for a coverage larger than 7 monolayers. As a first step in the study of this unusual behaviour, we report results of ab-initio calculations of the magnetic order of Ni films on a Cu(001) substrate. The magnetic moments are computed by means of the real-space Tight-Binding LMTO method allowing non-collinear magnetic moments and including spin-orbit coupling to account for magnetic anisotropy effects. As the number of Ni layers is increased, we discuss the stability of the system with a magnetization in-plane or out-of-plane.

scholarly journals Magnetic anisotropy of graphene quantum dots decorated with a ruthenium adatom

2013 ◽  
Vol 4 ◽  
pp. 441-445 ◽  
Author(s):  
Igor Beljakov ◽  
Velimir Meded ◽  
Franz Symalla ◽  
Karin Fink ◽  
Sam Shallcross ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Density Functional ◽  
Magnetic Transition ◽  
Graphene Quantum Dots ◽  
Magnetic Storage ◽  
Magnetic Anisotropy Energy ◽  
Magnetization Direction ◽  
Storage Devices ◽  
Out Of Plane ◽  
Graphene Edge

The creation of magnetic storage devices by decoration of a graphene sheet by magnetic transition-metal adatoms, utilizing the high in-plane versus out-of-plane magnetic anisotropy energy (MAE), has recently been proposed. This concept is extended in our density-functional-based modeling study by incorporating the influence of the graphene edge on the MAE. We consider triangular graphene flakes with both armchair and zigzag edges in which a single ruthenium adatom is placed at symmetrically inequivalent positions. Depending on the edge-type, the graphene edge was found to influence the MAE in opposite ways: for the armchair flake the MAE increases close to the edge, while the opposite is true for the zigzag edge. Additionally, in-plane pinning of the magnetization direction perpendicular to the edge itself is observed for the first time.

scholarly journals Low-field Magnetic Anisotropy of Sr2IrO4

2022 ◽  
Author(s):  
Muhammad Nauman ◽  
Tayyaba Hussain ◽  
Joonyoung Choi ◽  
Nara Lee ◽  
Young Jai Choi ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Exchange Interaction ◽  
Exchange Interactions ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Easy Magnetization ◽  
Magnetic Exchange ◽  
Crystal Field Effect ◽  
Out Of Plane

Abstract Magnetic anisotropy in strontium iridate (Sr2IrO4) is essential because of its strong spin–orbit coupling and crystal field effect. In this paper, we present a detailed mapping of the out-of-plane (OOP) magnetic anisotropy in Sr2IrO4 for different sample orientations using torque magnetometry measurements in the low-magnetic-field region before the isospins are completely ordered. Dominant in-plane anisotropy was identified at low fields, confirming the b axis as an easy magnetization axis. Based on the fitting analysis of the strong uniaxial magnetic anisotropy, we observed that the main anisotropic effect arises from a spin–orbit-coupled magnetic exchange interaction affecting the OOP interaction. The effect of interlayer exchange interaction results in additional anisotropic terms owing to the tilting of the isospins. The results are relevant for understanding OOP magnetic anisotropy and provide a new way to analyze the effects of spin–orbit-coupling and interlayer magnetic exchange interactions. This study provides insight into the understanding of bulk magnetic, magnetotransport, and spintronic behavior on Sr2IrO4 for future studies.

scholarly journals Magnetic competition in topological kagome magnets

2021 ◽  
Author(s):  
Thanh-Mai Thi Tran ◽  
Duong-Bo Nguyen ◽  
Hong-Son Nguyen ◽  
Minh-Tien Tran
Keyword(s):  
Variational Principle ◽  
Spin Exchange ◽  
Tight Binding ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Zero Temperature ◽  
Electron Dynamics ◽  
Hall Conductance ◽  
Magnetic Phases ◽  
Out Of Plane

Abstract Magnetic competition in topological kagome magnets is studied by incorporating the spin-orbit coupling, anisotropic Hund coupling and spin exchange into a tight-binding electron dynamics in the kagome lattice. Using the Bogoliubov variational principle we find the stable phases at zero and finite temperatures. At zero temperature and in the strong Ising-Hund coupling regime, a magnetic tunability from the out-of-plane ferromagnetism to the in-plane antiferromagnetism is achieved through a universal property of the critical in-plane Hund coupling. At low temperature the out-of-plane ferromagnetism is stable until a finite crossing temperature. Above the crossing temperature the in-plane antiferromagnetism is stable, but the magnetization of the out-of-plane ferromagnetism still survives. This suggests a metastable coexistence of these magnetic phases in a finite temperature range. A large anomalous Hall conductance is observed in the Ising-Hund coupling limit.

Stability, Electronic and Magnetic Properties of Ca3Ru2O7

2011 ◽  
Vol 217-218 ◽  
pp. 924-929
Author(s):  
Jin Hong Xue ◽  
Jing Chao Chen ◽  
Jie Yu ◽  
Jing Feng ◽  
Yong Pan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Cohesive Energy ◽  
Density Functional ◽  
Theoretical Study ◽  
Magnetic Moments ◽  
Covalent Bonds ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
The Stability

Ca3Ru2O7 is new tpye of thermoelectric materials.A theoretical study is presented for the stability, electronic and magnetic properties of three phases of this new thermoelectric materials in the framework of density functional theory (DFT). The calculated cohesive energy is -7.94eV/unit. AFM2 are less stable than other pahses. Electronic calculations indicate that Ca3Ru2O7 is metallic in nature. The covalent bonds in these structures are due to orbital overlap between p bands of O and d bands of Ru, and DOS at Fermi level are dominated by d bands of Ru. FM phase have obvious magnetic moments.

Stepped Fe(100) and V/Fe(100) Magnetism

1991 ◽  
Vol 231 ◽  
Author(s):  
A. Vega ◽  
A. Rubio ◽  
L.C. Balbas ◽  
J. Dorantes-Davila ◽  
C. Demangeat ◽  
...  
Keyword(s):  
Transition Metal ◽  
Flat Surface ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Step Length ◽  
Real Space ◽  
External Edge ◽  
Transition Metal Surface ◽  
Self Consistent ◽  
Stepped Surface

AbstractWe have investigated the magnetic arrangment of 3d transition-metal stepped surface by using a self-consistent real-space tight-binding method. As expected, the presence of steps modifies locally the properties of a transition-metal surface. We emphasized the influence of atomic environment. We found for the (100)-Fe surface, an enhancement of the magnetic moments of the external edge of this step as compared to the flat surface. The results are not very sensitives to the step length. More striking is the case of the (100)-V stepped surface where atoms at the external edge display a large magnetic moment.

scholarly journals Superconductivity assisted change of the perpendicular magnetic anisotropy in V/MgO/Fe junctions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
César González-Ruano ◽  
Diego Caso ◽  
Lina G. Johnsen ◽  
Coriolan Tiusan ◽  
Michel Hehn ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Applied Field ◽  
Perpendicular Magnetic Anisotropy ◽  
Spin Orbit Coupling ◽  
Superconducting Transition ◽  
Spin Electronics ◽  
Superconducting Vortices ◽  
Out Of Plane ◽  
Experimental Findings ◽  
Metal Bilayers

AbstractControlling the perpendicular magnetic anisotropy (PMA) in thin films has received considerable attention in recent years due to its technological importance. PMA based devices usually involve heavy-metal (oxide)/ferromagnetic-metal bilayers, where, thanks to interfacial spin-orbit coupling (SOC), the in-plane (IP) stability of the magnetisation is broken. Here we show that in V/MgO/Fe(001) epitaxial junctions with competing in-plane and out-of-plane (OOP) magnetic anisotropies, the SOC mediated interaction between a ferromagnet (FM) and a superconductor (SC) enhances the effective PMA below the superconducting transition. This produces a partial magnetisation reorientation without any applied field for all but the largest junctions, where the IP anisotropy is more robust; for the smallest junctions there is a reduction of the field required to induce a complete OOP transition ($$H_\text {OOP}$$ H OOP ) due to the stronger competition between the IP and OOP anisotropies. Our results suggest that the degree of effective PMA could be controlled by the junction lateral size in the presence of superconductivity and an applied electric field. We also discuss how the $$H_\text {OOP}$$ H OOP field could be affected by the interaction between magnetic stray fields and superconducting vortices. Our experimental findings, supported by numerical modelling of the ferromagnet-superconductor interaction, open pathways to active control of magnetic anisotropy in the emerging dissipation-free superconducting spin electronics.

scholarly journals Low-Field Magnetic Anisotropy of Sr2IrO4

2021 ◽  
Author(s):  
Muhammad Nauman ◽  
Tayyaba Hussain ◽  
Joonyoung Choi ◽  
Nara Lee ◽  
Young Jai Choi ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Exchange Interaction ◽  
Exchange Interactions ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Easy Magnetization ◽  
Magnetic Exchange ◽  
Crystal Field Effect ◽  
Out Of Plane

Abstract Magnetic anisotropy in strontium iridate (Sr2IrO4) is essential because of its strong spin-orbit coupling and crystal field effect. In this study, we investigated the detailed mapping of the out-of-plane (OOP) magnetic anisotropy in Sr2IrO4 for different sample orientations using torque magnetometry measurements in the low-magnetic-field region before the isospins are fully ordered. Dominant in-plane anisotropy was identified at low fields, confirming the b axis as an easy magnetization axis. Based on the fitting analysis of the strong uniaxial magnetic anisotropy, we observed that the main anisotropic effect arises from a spin–orbit-coupled magnetic exchange interaction that affects the OOP interaction. The interlayer exchange interaction results in additional anisotropic terms owing to the tilting of the isospins. Our results are relevant for understanding OOP magnetic anisotropy and provide a new way to analyze the effects of spin–orbit-coupling and interlayer magnetic exchange interactions. This study provides a new insight into the understanding of bulk magnetic, magneto-transport, and spintronic behavior of Sr2IrO4 for future studies.

scholarly journals Interfacial coupling effect of Cr2O3 on the magnetic properties of Fe72Ga28 thin films

2021 ◽  
Author(s):  
I. Hontecillas ◽  
M. Maicas ◽  
J. P. Andrés ◽  
R. Ranchal
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Coupling Effect ◽  
Interfacial Coupling ◽  
Bias Effect ◽  
Exchange Bias Effect ◽  
Magnetization Direction ◽  
Sample Plane ◽  
Out Of Plane

Abstract Here it is investigated the effect of the antiferromagnet Cr2O3 on the magnetic properties of ferromagnetic Fe72Ga28 thin films. Although Fe72Ga28 layers have their magnetization almost in the sample plane, the interfacial coupling with Cr2O3 that has perpendicular magnetic moments enables to turn the Fe72Ga28 magnetization direction into the out of plane (OOP) direction. Cr2O3 has been obtained from Cr oxidation, whereas Fe72Ga28 has been deposited on top of it by sputtering in the ballistic regime. Although a uniaxial in-plane magnetic anisotropy is expected for Fe72Ga28 thickness above 100 nm, the interfacial coupling with Cr2O3 prevents this anisotropy. The formation of stripe domains in Fe72Ga28 above a critical thickness reveals the enhancement of the out of plane component of the Fe72Ga28 magnetization with respect to uncoupled layers. Due to the interface coupling, the Fe72Ga28 magnetization turns into the out-of-plane direction as its thickness is gradually reduced, and a perpendicular magnetic anisotropy of 3.4·106 erg·cm− 3 is inferred from experimental results. Eventually, the coupling between Cr2O3 and Fe72Ga28 promotes an exchange-bias effect that has been well fitted by means of the random field model.

CALCULATION FOR A Cu(001) SURFACE WITH AN IMPURITY ATOM

1999 ◽  
Vol 13 (04) ◽  
pp. 389-396
Author(s):  
CHIH-KAI YANG
Keyword(s):  
Electronic Structure ◽  
Impurity Atom ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Real Space ◽  
Structure Calculation ◽  
Spin Polarized ◽  
Densities Of States ◽  
Self Consistent ◽  
Local Densities

I use a self-consistent electronic structure calculation to study the system of Cu(001) that has an impurity atom replacing one of the surface Cu atoms. The calculation makes use of the tight-binding linear muffin-tin orbitals (TB-LMTO) and is carried out in real space. I am able to derive the spin-polarized local densities of states for the impurity Cr and Fe respectively, which have peaks below the Fermi level. Charge transfers between the impurities and their neighbors also result in different distributions of magnetic moments for the two impurity systems, with the Cr having approximately 0.5μ B and the Fe atom having a negligible magnetic moment.

Sign in / Sign up

Export Citation Format

Share Document