Tight-binding approach to the orbital magnetic moment and magnetocrystalline anisotropy of transition-metal monolayers

Bruno, P.

doi:10.1103/physrevb.39.865

Cited by 1,295 publications

(928 citation statements)

References 19 publications

Supporting

Mentioning

850

Contrasting

Unclassified

Order By: Relevance

“…Applying the deposition field along the interfacial uniaxial easy-axis produces an increase in the component of the ratio of the atomic species resolved orbital and spin magnetic moments, m l /m s , directed along the uniaxial easy axis of magnetization, whilst applying the deposition field along the uniaxial hard-axis causes a decrease, as summarized in table 3. The ratio m l /m s along the easy-axis may be taken as representative of the degree of anisotropy in the orbital magnetic moment, and hence as a measure of the magnetic anisotropy itself 27 . The spin-orbit contribution to the uniaxial magnetic anisotropy is ∆E SO ∝ −m l · m s ∼ −m l 34 ; hence the deposition field changes the maximal projection of the atomic orbital magnetic moments onto the easy-axis, which corresponds to a deposition-field-induced shift in the free-energy landscape via a modification of the contribution of the spin-orbit interaction to the total energy.…”

Section: Modification Of the Volume Uniaxial Anisotropy Termmentioning

confidence: 99%

“…For both films the ratio of orbital to spin magnetic moments are extracted using sum-rule analysis 105 , and are found to be m l /m s = 0.21 for Co, and m l /m s = 0.11 for Fe (not shown), apparently independent of the underlying semiconductor material. For a ferromagnet with only uniaxial anisotropy, m l /m s measured along the uniaxial easy axis should be proportional to the degree of anisotropy in m l , and hence to the effective uniaxial magnetic anisotropy 25,27 . However, in this case there is also a volume cubic magnetocrystalline anisotropy with similar strength to the interface induced uniaxial magnetic anisotropy: the measured anisotropy in m l is due predominantly to the magnetocrystalline anisotropy, owing to the short penetration-depth of electron-yield XMCD.…”

Section: Removal Of the Magnetoelastic Anisotropy Termmentioning

confidence: 99%

See 1 more Smart Citation

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Hindmarch

2011

SPIN

View full text Add to dashboard Cite

Interfaces between dissimilar materials present a wide range of fascinating physical phenomena. When a nanoscale thin-film of a ferromagnetic metal is deposited in intimate contact with a compound semiconductor, the properties of the interface exhibit a wealth of novel behavior, having immense potential for technological application, and being of great interest from the perspective of fundamental physics. This article presents a review of recent advances in the field of interface magnetism in (001)-oriented ferromagnetic metal/III–V compound semiconductor hybrid structures. Until relatively recently, the majority of research in this area continued to concentrate almost exclusively on the prototypical epitaxial Fe / GaAs (001) system: now, a significant proportion of work has branched out from this theme, including ferromagnetic metal alloys, and other III–V compound semiconductors. After a general overview of the topic, and a review of the more recent literature, we discuss recent results where advances have been made in our understanding of the physics underpinning magnetic anisotropy in these systems: tailoring the terms contributing to the angular-dependent free-energy density by employing novel fabrication methods and ferromagnetic metal electrodes.

show abstract

Section: Modification Of the Volume Uniaxial Anisotropy Termmentioning

confidence: 99%

Section: Removal Of the Magnetoelastic Anisotropy Termmentioning

confidence: 99%

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Hindmarch

2011

SPIN

View full text Add to dashboard Cite

show abstract

“…E so = Cξ m o /4μ B [34]. A correction factor C must be applied since the energy calculated using this expression can be up to 20 times bigger than the value measured macroscopically [29].…”

Section: B Hysteresis Loopsmentioning

confidence: 99%

“…Although the magnetocrystalline anisotropy in 3d TM magnetic metals is usually associated with the anisotropy of the orbital moment ( m o ) [34,35], the exact quantification of its energy needs to take into account other factors related to their atomic environment [30][31][32]. Our study will show that in NdCo alloys, this energy gets higher and it competes with that of the neodymium subnetwork when the cobalt magnetic moment gets more localized by bonding to neodymium, which it does without having to increase m o but increases its orbital moment to spin ratio m o /m s .…”

Section: Introductionmentioning

confidence: 99%

Perpendicular magnetic anisotropy in amorphous NdxCo1−x thin films studied by x-ray magnetic circular dichroism

et al. 2017

View full text Add to dashboard Cite

The origin of perpendicular magnetic anisotropy (PMA) in amorphous Nd x Co 1−x thin films is investigated using x-ray magnetic circular dichroism (XMCD) spectroscopy at the Co L 2,3 and Nd M 4,5 edges. The magnetic orbital and spin moments of the 3d cobalt and 4f neodymium electrons were measured as a function of the magnetic field orientation, neodymium concentration, and temperature. In all the studied samples, the magnetic anisotropy of the neodymium subnetwork is always oriented perpendicular to the plane, whereas the anisotropy of the orbital moment of cobalt is in the basal plane. The ratio L z /S z of the neodymium 4f orbitals changes with the sample orientation angle, being higher and closer to the atomic expected value at normal orientation and smaller at grazing angles. This result is well explained by assuming that the 4f orbital is distorted by the effect of an anisotropic crystal field when it is magnetized along its hard axis, clearly indicating that the 4f states are not rotationally invariant. The magnetic anisotropy energy associated to the neodymium subnetwork should be proportional to this distortion, which we demonstrate is accessible by applying the XMCD sum rules for the spin and intensity at the Nd M 4,5 edges. The analysis unveils a significant portion of neodymium atoms magnetically uncoupled to cobalt, i.e., paramagnetic, confirming the inhomogeneity of the films and the presence of a highly disordered neodymium rich phase already detected by extended x-ray-absorption fine structure (EXAFS) spectroscopy. The presence of these inhomogeneities is inherent to the evaporation preparation method when the chosen concentration in the alloy is far from its eutectic concentrations. An interesting consequence of the particular way in which cobalt and neodymium segregates in this system is the enhancement of the cobalt spin moment which reaches 1.95 μ B in the sample with the largest segregation.

show abstract

“…In bulk form 29 and in thin films 30 , it has a magnetization compensation temperature and a spin reorientation temperature. As the orbital moment of Dy is nearly as large as the spin moment 31 , it is expected that DyCo 5 exhibits a large perpendicular anisotropy 32 , which qualifies it as a robust pinning layer. Owing to the vanishing orbital moment of Gd, the perpendicular magnetic anisotropy of Fe 76 Gd 24 (FeGd) is weak.…”

mentioning

confidence: 99%

Perpendicular exchange bias in ferrimagnetic spin valves

et al. 2012

View full text Add to dashboard Cite

The exchange bias effect refers to the shift of the hysteresis loop of a ferromagnet in direct contact to an antiferromagnet. For applications in spintronics a robust and tunable exchange bias is required. Here we show experimental evidence for a perpendicular exchange bias in a prototypical ferrimagnetic spin valve consisting of DyCo 5 /Ta/Fe 76 Gd 24 , where the DyCo 5 alloy has the role of a hard ferrimagnet and Fe 76 Gd 24 is a soft ferrimagnet. Taking advantage of the tunability of the exchange coupling between the ferrimagnetic layers by means of thickness variation of an interlayer spacer, we demonstrate that perpendicular unidirectional anisotropy can be induced with desirable absolute values at room temperature, without making use of a field-cooling procedure. moreover, the shift of the hysteresis loop can be reversed with relatively low magnetic fields of several hundred oersteds. This flexibility in controlling a robust perpendicular exchange bias at room temperature may be of crucial importance for applications.

show abstract

Tight-binding approach to the orbital magnetic moment and magnetocrystalline anisotropy of transition-metal monolayers

Cited by 1,295 publications

References 19 publications

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

Perpendicular magnetic anisotropy in amorphous NdxCo1−x thin films studied by x-ray magnetic circular dichroism

Perpendicular exchange bias in ferrimagnetic spin valves

Contact Info

Product

Resources

About