Nuclear magnetic resonance in ferromagnets: Ferromagnetic nuclear resonance; a very broadband approach

Mény, C.; Panissod, P.

doi:10.1016/bs.arnmr.2021.02.001

Cited by 7 publications

(15 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These spectra, having most of their spectral weight in the 210-230 MHz range, are typical for polycrystalline cobalt samples. [19,32] The AlCo and C 60 Co films exhibit maximum intensity at ≈222 MHz, closer to the 59 Co resonance reported for hcp cobalt, while the main peak of Gaq 3 Co is found at ≈215 MHz, close the 59 Co peak of the fcc phase. [16] It is unlikely that these samples are characterized by different microstructures since for each sample the growth of the Co pristine layer has been done during the same deposition, ensuring the same thickness, morphology, and crystalline composition.…”

Section: Fnr and L-moke Investigationsupporting

confidence: 72%

“…This corresponds to a decrease in the mean enhancement factor

\bar{\eta } \propto 1/\sqrt {{\rm{P}}_{{\rm{rf}}}^{({\rm{opt}})}}

. Within the adiabatic response of the electronic moments to the rf field, [ 21,25 ] η is proportional to the dc transverse magnetic susceptibility, [ 19 ] in its turn inversely proportional to the combination of the magneto‐crystalline anisotropy, the demagnetization and the applied field (if present). This is accounted for by the effective restoring field H R , defined as the equivalent magnetic field exerting a torque on the electronic spins tilted from their equilibrium direction.…”

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

“…This is accounted for by the effective restoring field H R , defined as the equivalent magnetic field exerting a torque on the electronic spins tilted from their equilibrium direction. [ 19,21 ] Therefore, the progressive shift to higher optimum excitation power, hence to higher

{{\rm{H}}_{\rm{R}}} \propto \sqrt {{\rm{P}}_{{\rm{rf}}}^{({\rm{opt}})}}

, witnesses an increased magnetic hardness in C 60 Co and even more markedly in Gaq 3 Co with respect to capped cobalt layer (AlCo).…”

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

“…Note that the electronic magnetic moments respond adiabatically, since the used excitation frequencies are far from any magnetic electronic resonance. [ 19 ]…”

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

See 3 more Smart Citations

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

Benini

Allodi

Surpi

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

The hybridization of the surface orbitals of thin ferromagnetic layers with molecular orbitals represents a soft but efficient technology that is able to induce in ferromagnetic component radical modifications of the key magnetic parameters, such as magnetization, magnetic anisotropy, and others. These effects are investigated in 7 nm thick polycrystalline Co films interfaced with C60 and Gaq3 molecular layers by combining 59Co Ferromagnetic nuclear resonance spectroscopy (FNR) and magneto‐optic kerr effect (MOKE) techniques. It is demonstrated that the surface hybridization produces a significant magnetic hardening with respect to a reference Co/Al system and that the molecule‐induced effects modify the magnetic properties of entire Co layer, propagating for several nm from the interface. The FNR spectroscopy also reveals a reconstruction of the magnetic environment at the cobalt surface, whose observation in polycrystalline films is especially intriguing. The results shed new and unexpected light on the interfacial physics in such systems, whose understanding necessitates further experimental and theoretical research.

show abstract

Section: Fnr and L-moke Investigationsupporting

confidence: 72%

“…This corresponds to a decrease in the mean enhancement factor

\bar{\eta } \propto 1/\sqrt {{\rm{P}}_{{\rm{rf}}}^{({\rm{opt}})}}

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

{{\rm{H}}_{\rm{R}}} \propto \sqrt {{\rm{P}}_{{\rm{rf}}}^{({\rm{opt}})}}

, witnesses an increased magnetic hardness in C 60 Co and even more markedly in Gaq 3 Co with respect to capped cobalt layer (AlCo).…”

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

“…Note that the electronic magnetic moments respond adiabatically, since the used excitation frequencies are far from any magnetic electronic resonance. [ 19 ]…”

Section: Fnr and L‐moke Investigationmentioning

confidence: 99%

See 2 more Smart Citations

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

Benini

Allodi

Surpi

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

show abstract

“…The structure of the Co films is further investigated by ferromagnetic nuclear resonance (FNR; nuclear magnetic resonance for ferromagnets). 27 The observed spectra are consistent with hcp Co having a magnetization direction perpendicular to the hcp c-axis 28 as expected for an in-plane magnetized hcp [0001] Co film. The quantitative analyses of the FNR spectra revealed an fcc Co content of about 30% (see supplementary Fig.…”

Section: Experimental Methodssupporting

confidence: 81%

Exchange bias at the organic/ferromagnet interface may not be a spinterface effect

Avedissian

Arabski

Wytko

et al. 2022

Applied Physics Reviews

Self Cite

View full text Add to dashboard Cite

Exchange bias is a physical effect that is used in many spintronic devices like magnetic read heads, MRAMS, and most kinds of magnetic sensors. For the next generation of fully organic devices, molecular exchange bias, if existing, could have a huge impact for developing mechanically soft and environment friendly devices. The observation of molecular exchange bias has been reported recently in hybrid systems where a metallic ferromagnet is exchanged biased by an organic film, and it is considered to be a spinterface effect. To understand this effect, we investigate if the molecular exchange bias exists in Co/metal tetra-phenyl porphyrin hybrid bilayer systems. Molecular exchange bias is never observed when the samples are properly encapsulated, and when exchange bias is eventually observed, it is not a spinterface effect, but it results from air-driven partial oxidation of the cobalt film transforming part of the metallic cobalt into a cobalt oxide that is well known to induce exchange bias effects. Surprisingly, oxidation is very difficult to prevent even by using very thick metallic encapsulating layers. A similar effect is observed in the Co/metal-phthalocyanine bilayer system showing that molecular exchange bias is not a spinterface effect also in the hybrid system in which this effect was originally discovered.

show abstract

Ubiquitous Order‐Disorder Transition in the Mn Antisite Sublattice of the (MnBi₂Te₄)(Bi₂Te₃)_n Magnetic Topological Insulators

Sahoo,

Onuorah,

Folkers

et al. 2024

Advanced Science

View full text Add to dashboard Cite

Magnetic topological insulators (TIs) herald a wealth of applications in spin‐based technologies, relying on the novel quantum phenomena provided by their topological properties. Particularly promising is the (MnBi2Te4)(Bi2Te3)n layered family of established intrinsic magnetic TIs that can flexibly realize various magnetic orders and topological states. High tunability of this material platform is enabled by manganese–pnictogen intermixing, whose amounts and distribution patterns are controlled by synthetic conditions. Here, nuclear magnetic resonance and muon spin spectroscopy, sensitive local probe techniques, are employed to scrutinize the impact of the intermixing on the magnetic properties of (MnBi2Te4)(Bi2Te3)n and MnSb2Te4. The measurements not only confirm the opposite alignment between the Mn magnetic moments on native sites and antisites in the ground state of MnSb2Te4, but for the first time directly show the same alignment in (MnBi2Te4)(Bi2Te3)n with n = 0, 1 and 2. Moreover, for all compounds, the static magnetic moment of the Mn antisite sublattice is found to disappear well below the intrinsic magnetic transition temperature, leaving a homogeneous magnetic structure undisturbed by the intermixing. The findings provide a microscopic understanding of the crucial role played by Mn–Bi intermixing in (MnBi2Te4)(Bi2Te3)n and offer pathways to optimizing the magnetic gap in its surface states.

show abstract

Nuclear magnetic resonance in ferromagnets: Ferromagnetic nuclear resonance; a very broadband approach

Cited by 7 publications

References 64 publications

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

Exchange bias at the organic/ferromagnet interface may not be a spinterface effect

Ubiquitous Order‐Disorder Transition in the Mn Antisite Sublattice of the (MnBi₂Te₄)(Bi₂Te₃)_n Magnetic Topological Insulators

Contact Info

Product

Resources

About

Nuclear magnetic resonance in ferromagnets: Ferromagnetic nuclear resonance; a very broadband approach

Cited by 7 publications

References 64 publications

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

In‐Depth NMR Investigation of the Magnetic Hardening in Co Thin Films Induced by the Interface with Molecular Layers

Exchange bias at the organic/ferromagnet interface may not be a spinterface effect

Ubiquitous Order‐Disorder Transition in the Mn Antisite Sublattice of the (MnBi2Te4)(Bi2Te3)n Magnetic Topological Insulators

Contact Info

Product

Resources

About

Ubiquitous Order‐Disorder Transition in the Mn Antisite Sublattice of the (MnBi₂Te₄)(Bi₂Te₃)_n Magnetic Topological Insulators