Random and exchange anisotropy in consolidated nanostructured Fe and Ni: Role of grain size and trace oxides on the magnetic properties

Löffler, Jörg F.; Meier, J.; Doudin, B.; Ansermet, Jean-Philippe; Wagner, W.

doi:10.1103/physrevb.57.2915

Cited by 180 publications

(109 citation statements)

References 41 publications

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“…1c). The electrode saturation magnetization M s ¼ 290 kA m À1 is B60% of the bulk value for Ni due to voids (nanocrystallinity forces only a 5% reduction 32 ). At remanence, a finite M z (upper inset, Fig.…”

Section: Resultsmentioning

confidence: 99%

Non-volatile electrically-driven repeatable magnetization reversal with no applied magnetic field

et al. 2013

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Repeatable magnetization reversal under purely electrical control remains the outstanding goal in magnetoelectrics. Here we use magnetic force microscopy to study a commercially manufactured multilayer capacitor that displays strain-mediated coupling between magnetostrictive Ni electrodes and piezoelectric BaTiO 3 -based dielectric layers. In an electrode exposed by polishing approximately normal to the layers, we find a perpendicularly magnetized feature that exhibits non-volatile electrically driven repeatable magnetization reversal with no applied magnetic field. Using micromagnetic modelling, we interpret this nominally full magnetization reversal in terms of a dynamic precession that is triggered by strain from voltage-driven ferroelectric switching that is fast and reversible. The anisotropy field responsible for the perpendicular magnetization is reversed by the electrically driven magnetic switching, which is, therefore, repeatable. Our demonstration of non-volatile magnetic switching via volatile ferroelectric switching may inspire the design of fatigue-free devices for electric-write magnetic-read data storage.

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Section: Resultsmentioning

confidence: 99%

Non-volatile electrically-driven repeatable magnetization reversal with no applied magnetic field

et al. 2013

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“…According to RAM, when particle size is above the ferromagnetic exchange length(L ex ), the H C increases with decreasing the particle size, and for the particle size below L ex , the H C decreases with decreasing the particle size. Generally, the value of L ex ∼30 nm, for pure iron [29,39] and expected to vary only slightly for iron nitride thin films. [40] In the present case observed variation in the H C does not correlate with the change in the crystallite size with increasing R N2 [see figure 2].…”

Section: Resultsmentioning

confidence: 99%

Study of magnetic iron nitride thin films deposited by high power impulse magnetron sputtering

Tayal

Gupta

et al. 2015

Surface and Coatings Technology

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In this work, we studied phase formation, structural and magnetic properties of iron-nitride (Fe-N) thin films deposited using high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (dc-MS). The nitrogen partial pressure during deposition was systematically varied both in HiPIMS and dc-MS. Resulting Fe-N films were characterized for their microstructure, magnetic properties and nitrogen concentration. We found that HiPIMS deposited Fe-N films show a globular nanocrystalline microstructure and improved soft magnetic properties. In addition, it was found that the nitrogen reactivity impedes in HiPIMS as compared to dc-MS. Obtained results can be understood in terms of distinct plasma properties of HiPIMS.

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“…Hence, for t FeCoV ӷ700 Å, H c should tend towards a smaller value of the order of the bulk value of 3 Oe. In the case of the FeCoV/TiN x , the maximum may be observed for t FeCoV Ͼ700 Å. Löffler et al 31 have explained the increase in H c with decreasing grain size until the maximum, in nanostructured Fe, by domain wall pinning at grain boundaries that becomes progressively more efficient as the volume fraction of the grain boundaries increases. In our case, the pinning effect can come from both FeCoV grain boundaries and interfaces of the multilayer structure.…”

Section: Hysteresis Behaviormentioning

confidence: 99%

“…Löffler et al 31 have reported coercivity in nanostructured Fe. In this case, H c increases from 5 Oe for the grain size of 100 Å to 100 Oe for about 350 Å.…”

Section: Hysteresis Behaviormentioning

confidence: 99%

“…They have explained the behavior of H c for the grain sizes between 100 and 350 Å by a random anisotropy model. 31 For random orientation of the anisotropy axes of the grains, the effective anisotropy is remarkably reduced. This model shows a decrease of the anisotropy energy and consequently a decrease of H c with decreasing grain size.…”

Section: Hysteresis Behaviormentioning

confidence: 99%

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Influence of interstitial nitrogen on the structural and magnetic properties of FeCoV/TiNx multilayers

Kumar

Böni

2002

Journal of Applied Physics

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Influence of dynamical dipolar coupling on spin-torque-induced excitations in a magnetic tunnel junction nanopillar J. Appl. Phys. 111, 07C906 (2012) Quasi-omnidirectional electrical spectrometer for studying spin dynamics in magnetic tunnel junctions Rev. Sci. Instrum. 83, 024710 (2012) Thermal-magnetic-electric oscillator based on spin-valve effect J. Appl. Phys. 111, 044315 (2012) Dependence of spin-transfer switching characteristics in magnetic tunnel junctions with synthetic free layers on coupling strength J. Appl. Phys. 111, 07C905 (2012) Electrical manipulation of spin polarization and generation of giant spin current using multi terminal spin injectors J. Appl. Phys. 111, 07C505 (2012) Additional information on J. Appl. Phys. FeCoV/TiN x and FeCoV/Ti multilayers having t FeCoV ϭ30-700 Å prepared by dc magnetron sputtering are investigated by x-ray diffraction, stress, and magnetization measurements. The x-ray diffraction data of the FeCoV/TiN x system show the presence of interstitial N atoms in the FeCoV layers due to reactive sputtering of Ti with nitrogen. The interstitial N causes an expansion of the FeCoV lattice in FeCoV/TiN x for small t FeCoV . However, for the samples with large t FeCoV , no lattice expansion is observed. In addition to the lattice expansion caused by the intake of N atoms, a change in the crystalline texture of FeCoV layers is also observed as indicated by the enhancement of the FeCoV͑200͒ peaks. The magnetic hysteresis measurements on the samples show that the easy direction of magnetization lies in the plane of the layers. They further show that there are easy and hard axes of magnetization within the plane of the FeCoV layers. The stress anisotropy present in the plane of the samples induces a magnetic anisotropy through magnetostrictive effects leading to the formation of the in-plane easy axis. The hysteresis and stress measurements carried out on these samples clearly show the influence of N on the in-plane magnetic anisotropy. The magnetoelastic energy in the case of the FeCoV/TiN x system, calculated from the stress data and from the magnetization measurements as a function of t FeCoV is found to agree over a large range of thickness, whereas the curves deviate significantly for small layer thickness. This deviation may be due to the role of the FeCoVN x phase. Hysteresis measurements also show that the remanence is about 95% for all the samples of the FeCoV/TiN x system. In contrast, the coercivity increases linearly with increasing t FeCoV in this system. The coercivity of the FeCoV/Ti system is larger and increases more rapidly with t FeCoV , as compared with the FeCoV/TiN x system. This behavior is attributed to a smaller grain size in the FeCoV/TiN x system due to the reactive sputtering of the Ti layers. However, there is no significant influence of N on the saturation magnetization of both systems.

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Random and exchange anisotropy in consolidated nanostructured Fe and Ni: Role of grain size and trace oxides on the magnetic properties

Cited by 180 publications

References 41 publications

Non-volatile electrically-driven repeatable magnetization reversal with no applied magnetic field

Non-volatile electrically-driven repeatable magnetization reversal with no applied magnetic field

Study of magnetic iron nitride thin films deposited by high power impulse magnetron sputtering

Influence of interstitial nitrogen on the structural and magnetic properties of FeCoV/TiNx multilayers

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