Magnetic Anisotropy Parameters Research Articles

Fabrication of rare earth dysprosium doped Ca-Cu (1:1) based Ca0.5Cu0.5Fe12–xDyxO19 ferrites for structural and magnetic investigations

Hexaferrites' magnetic and structural properties are highly sensitive to changes in sintering temperature and cationic replacements. We fabricated Ca0.5Cu0.5Fe12–xDyxO19 hexaferrites using the sol-gel technique. We examined the phase, microstructure and magnetic aspects of the samples with respect to varying doping of rare earth dysprosium. The results show the expansion in the lattice upon incorporation of dysprosium against iron. Morphological studies confirm the uniform distribution of particles with slightly longitudinal nanoflakes in one direction. Magnetic investigations show an increase in magnetic saturation (Ms) with increasing dysprosium incorporation till optimum level is achieved for 15% doping concentration, with negligible change for maximum doping level. Furthermore, coercivity (Hc) and magnetic moment (mB) in terms of Bohr’s magneton (μB) also show an increasing trend with dysprosium substitution levels. The maximum saturation magnetization of 33.355 emu/g is achieved with magnetic remanence of 18.290 emu/g, along with optimum magnetic moment of 6.249 μB. In addition to the traditional magnetic parameters, magnetic anisotropy parameters were explored for the deep insights into magnetic parameters. These outcomes suggest that improved magnetic properties of Ca0.5Cu0.5Fe12–xDyxO19 ferrites make it good substitute for storage devices, magnetic filters, and other magnetic applications.

Evaluation of measuring magnetic anisotropy parameters method to monitor the development of erosion and corrosion wear of equipment

The paper presents the results of further research in the field of assessing the development of erosion and corrosion wear (ECW) of pipeline elements using a magnetic and anisotropic method to monitor the stress-strain state of ferromagnetic material. The conducted studies show that the recorded parameters of the magnetic anisotropic method, such as the principal mechanical stress difference, make it possible to unambiguously establish a quantitative correspondence to the level of stresses operating in the controlled zone. The possibility of determining the correspondence of the level of effective stresses to the value of the principal mechanical stress difference recorded by the StressVision scanner during the inspection of the structure is proven. The paper shows that in order to organize monitoring of the development of ECW using the magnetic anisotropic method it is necessary to monitor periodically changes in the principal mechanical stress difference and its dispersion and when fixing cut-off points, prescribe additional examinations with other more labor-intensive methods. The possibility of organizing monitoring of ECW equipment development based on the use of a pipeline resource forecasting mechanism in accordance with the provisions of regulatory documentation is confirmed.

Electronic and Magneto-Electric properties of YFeO3

In this study, we have thoroughly investigated the electronic, magnetic, and electrical properties of yttrium orthoferrite using density functional theory (DFT) within the generalized gradient approximation (GGA) and the (GGA + U) approach, which incorporates the Hubbard term (U). Both approximations consistently reveal a semiconductor behavior and an antiferromagnetic behavior of type-G between the iron (Fe) ions. To delve deeper into the magnetic interactions within YFeO3, we have proposed a physical model. This model allows us to calculate the magnetic exchange coupling and magnetic anisotropy parameters through DFT calculations. Additionally, we have conducted computations to determine the electric polarization. Our results have shown that the electric polarization in YFeO3 is exclusively derived from electronic polarization. We have also explored the relationship between the direction of electric polarization and the easy-axis magnetization. In our investigation, we found that both the electric polarization and easy-axis magnetization align along the c-axis in both approximations. Furthermore, we have examined the influence of the Hubbard term on the direction of polarization. To assess the magnetic temperature transition, we employed Monte Carlo simulations using the Ising model. The critical temperature, denoted as TN, obtained with the GGA approximation is found to be 726.66 K. Remarkably, this value closely matches the experimental critical temperature when compared to the critical temperature obtained with the GGA + U approximation.

Impact of counter anions on structural and magnetic properties of iron(III) meso-tetraphenylporphyrin tetrahydrofurane solvates

Intensively researched iron meso-tetraphenylporphyrin (FeTPP) complexes are central to the functionalities of many biological systems while at the same time they possess intriguing magnetic properties. Here we report on the synthesis and structural characterization of FeTPP complexes with axial tetrahydrofuran (THF) ligand and different non-coordinating counter anions. Structurally, the most interesting feature of these complexes is the stretching of the distance between the iron(III) and the oxygen atom of the THF ligand for different counter anions. This parameter affects the magnetic anisotropy of FeTPP as studied here with magnetic susceptibility, χm, and X-band electron paramagnetic resonance (EPR). Both magnetic probes are consistent with the iron(III) in its high-field state S = 5/2. Simulations of temperature dependencies of χm and EPR spectra show that the zero-field splitting magnetic anisotropy parameter D decreases with the tetragonal elongation of the hexa-coordinated iron(III) geometry, which is qualitatively discussed within the ligand field theory.

Magnon-bandgap controllable artificial domain wall waveguide

In this paper, a magnon-bandgap controllable artificial domain wall waveguide is proposed by means of micromagnetic simulation. By the investigation of the propagation behavior and dispersion relationship of spin waves in artificial domain wall waveguides, it is found that the nonreciprocal propagation of spin waves in the artificial domain walls is mainly affected by the local effective exchange field, and the magnon bandgap can be controlled by changing the maximum value of the effective exchange field. In addition, it is observed that the artificial domain wall waveguides are structurally more stable than the natural domain wall waveguides under the same spin wave injection conditions, and the magnon bandgap of the artificial domain wall waveguides can be adjusted by its width and magnetic anisotropy parameters. The bandgap controllable artificial domain wall scheme is beneficial to the miniaturization and integration of magnon devices and can be applied to future magnonic technology as a high-pass filter with adjustable cutoff frequency.

Improvement of the magnon-magnon coupling strength in Y3Fe5O12/Py heterostructures

Magnon-quasiparticle couplings perform magnon information transferences and transports, thus controlling the coupling strengths is significant for novel information function devices. Here, we report the modulation of the magnon-magnon (M−M) coupling strength in Y3Fe5O12/permalloy (YIG/Py) heterostructures via ferromagnetic resonance (FMR) technique. The anti-crossing gap gc enhances 80 Hz by changing the radio frequency (rf) microwave power, which could be ascribed to the enhancement of the dipolar interaction and spin pumping effect. Furthermore, the gc decreases with the increasing angle θ between external magnetic field and rf current due to the increase of magnon relaxation. Moreover, the FMR linewidths change with increasing angle θ due to the magnetic anisotropy parameters and the two-magnon relaxation mechanism induced by the more oblique external field.

Multi-Technique Experimental Benchmarking of the Local Magnetic Anisotropy of a Cobalt(II) Single-Ion Magnet.

A comprehensive understanding of the ligand field and its influence on the degeneracy and population of d-orbitals in a specific coordination environment are crucial for the rational design and enhancement of magnetic anisotropy of single-ion magnets (SIMs). Herein, we report the synthesis and comprehensive magnetic characterization of a highly anisotropic CoII SIM, [L2Co](TBA)2 (L is an N,N'-chelating oxanilido ligand), that is stable under ambient conditions. Dynamic magnetization measurements show that this SIM exhibits a large energy barrier to spin reversal U eff > 300 K and magnetic blocking up to 3.5 K, and the property is retained in a frozen solution. Low-temperature single-crystal synchrotron X-ray diffraction used to determine the experimental electron density gave access to Co d-orbital populations and a derived U eff, 261 cm-1, when the coupling between the d x 2-y 2 and dxy orbitals is taken into account, in very good agreement with ab initio calculations and superconducting quantum interference device results. Powder and single-crystal polarized neutron diffraction (PNPD, PND) have been used to quantify the magnetic anisotropy via the atomic susceptibility tensor, revealing that the easy axis of magnetization is pointing along the N-Co-N' bisectors of the N,N'-chelating ligands (3.4° offset), close to the molecular axis, in good agreement with complete active space self-consistent field/N-electron valence perturbation theory to second order ab initio calculations. This study provides benchmarking for two methods, PNPD and single-crystal PND, on the same 3d SIM, and key benchmarking for current theoretical methods to determine local magnetic anisotropy parameters.

АНАЛІЗ МАГНІТНОЇ АНІЗОТРОПІЇ ЗРАЗКІВ ПОРІД ПОЛІГОНУ КРИВОРІЗЬКОЇ НАД ГЛИБОКОЇ СВЕРДЛОВИНИ

Understanding the reasons and principles of anisotropy of geological rocks opens the way to assess geodynamic processes in regions, enables to track changes of geological factors that form them, provides information about the structure and directions of the dynamics of geological rocks and etc. The aim of this study is the investigation of the nature of magnetic anisotropy of a collection of 26 samples that were taken from the well "Suputnyk-2" (490–2720 m) of the Kryvorizka extremely deep well. The samples consist of the following rocks: biotite schists, gneisses, ferruginous quartzites, muscovite quartzites, microcline-plagioclase granites. The authors used equipment of the KLY-2 series to measure the magnetic susceptibility of samples having the shape of cuberhombic decahedron. The authors have performed primary processing of measurement results and calculation of anisotropy parameters in the ANIZO10 program. The following parameters were determined as a result of the analysis: value of magnetic susceptibility (χ); statistical value of the standard deviation; normal values of magnetic susceptibility along three axes; coefficients characterizing magnetic anisotropy (H1 – H6); magnetic inclination angle (D) and magnetic inclination angle (I). The authors performed an initial classification of rocks based on the practical data processing scheme. Analyzing the calculations based on the ellipsoid of magnetic susceptibility, four rock classes were obtained: the shape of a sphere (12 %), a flattened shape (46 %), triaxial (23 %) and a complex ellipsoid shape (19 %). This indicates the complex geological conditions where rocks from the well "Suputnyk-2" (490–2720 m) were formed. It is confirmed that the samples belong to the VІІ–X tectonofacies according to the authors' previous research. The authors have investigated the coefficient of differential magnetic anisotropy, such as acoustic anisotropy. According to the results of the calculations, it was established that samples with low magnetic anisotropy are only 3.8 % of the total number of samples. Highly anisotropic samples of the collection comprise 53.8 % of the total number. It indicates the variety of processes that affected the rocks during their formation. According to the previous research of the authors, the coefficient of acoustic anisotropy of the well samples also varies from 2.8 to 24.9 %. The symmetry of the acoustic tensor in the majority of rock textures is rhombic. The final step in comparing the research results of the parameters of acoustic and magnetic anisotropy involved a tectonofacial analysis of the obtained data. It was determined that both magnetic and acoustic anisotropy coefficients, calculated from their respective tensors, reflect changes in tectonofacial conditions during the formation of the studied rocks.

Machine Learning Approach for Evaluation of Nanodefects and Magnetic Anisotropy in FePt Granular Films

This paper reports a machine learning approach for evaluating micromagnetic and microstructural parameters from demagnetization curves of FePt granular films for heat-assisted magnetic recording (HAMR) media. We developed a neural network to predict parameters of magnetic anisotropy and volume fractions of defects such as [200] misoriented grains, {111} twined variants, and disordered grains. The neural network was trained on a synthetic dataset of out-of-plane demagnetization curves that were simulated using the micromagnetic model constructed from actual nanostructure of a FePt-X HAMR medium. Predicted nanodefects agreed well with those estimated by synchrotron X-ray diffraction, and the demagnetization curve simulated with the predicted parameters accurately reproduced the experimental one. This work paves the way for a high-throughput magnetometry-based characterization of FePt granular media for its structural optimization toward higher areal density of HAMR.

Magnetoelectric effect and magnetization processes in garnet films

Changes in the domain structure of epitaxial bismuth-substituted iron-garnet films under joint action of AC electric field and DC magnetic field are investigated by the optical polarimetry method. Garnet films exhibit electric field dependent magnetic properties, which have been measured as a function of the applied magnetic field oriented in the plane of the film. The investigations have revealed that the electric field practically does not modify the film magnetization magnitude and the registered magnetoelectric effect is associated with the influence of the electric field on the magnetic anisotropy parameters of the investigated film.

Reconfigurable Logic Operations via Gate Controlled Skyrmion Motion in a Nanomagnetic Device

Owing to the topological protection and the ease of efficient manipulation, skyrmions have emerged as potential candidates for carrying information in future memory and logic devices. Here, we have proposed a reconfigurable skyrmion based two-input logic device architecture. Using micromagnetic simulations, we have demonstrated that the device is capable of performing both OR and AND logic gate functionalities in a reconfigurable manner. Different logic functionality of the device is selected by using a current through a nonmagnetic metallic gate, and the resultant Oersted field controls the trajectory of the skyrmion, which in turn determines the logic states. The logic functions are implemented on a ferromagnet/heavy metal bilayer device structure by virtue of several physical effects, such as the spin–orbit torque, skyrmion–edge repulsion, skyrmion–skyrmion topological repulsion, and skyrmion Hall effect. The skyrmion trajectory has been characterized by estimating the skyrmion Hall angle. A wide range of operations by varying the current density, skyrmion velocity, Dzyaloshinskii–Moriya interaction, magnetic anisotropy, and geometrical parameters have been presented in detail. We believe that our spin orbit torque driven logic design will have potential implications for a high-speed and low-power skyrmion based computing architecture.

Changing the Dynamic Parameters of Localized Breather and Soliton Waves in the Sine-Gordon Model with Extended Impurity, External Force, and Decay in the Autoresonance Mode

Possibility of changing the dynamic parameters of localized breather and soliton waves for the sine-Gordon equation in the model with extended impurity, variable external force and dissipation was investigated using the autoresonance method. The model of ferromagnetic structure consisting of two wide identical layers separated by a thin layer with modified values of magnetic anisotropy parameter was taken as a basis. Frequency of external field is a linear function of time. The sine-Gordon equation (SGE) was solved numerically using the finite differences method with explicit scheme of integration. For certain values of the extended impurity parameters a magnetic inhomogeneity in the form of magnetic breather is formed when domain wall passes through it with constant velocity. The numerical simulation showed that using special variable force and small amplitude it is possible to resonantly increase the amplitude of breather. For each case of the impurity parameters values, there is a threshold value of the magnetic field amplitude leading to resonance. Geometric parameters of thin layer also have influence on the resonance effect — for decreasing layer width the breather amplitude grows more slowly. For large layer width the translation mode of breather oscillations is also excited. For certain parameters of extended impurity, a soliton can form. For a special type of variable field with frequency linearly dependent on time, soliton is switched to antisoliton and vice versa.

Paramagnetic 7Li NMR Shifts and Magnetic Properties of Divalent Transition Metal Silylamide Ate Complexes [LiM{N(SiMe3)2}3] (M2+ = Mn, Fe, Co).

7Li NMR shifts and magnetic properties have been determined for three so-called ate complexes [LiM{N(SiMe3)2}3] (M2+ = Mn, Fe, Co; e.g., named lithium-tris(bis(trimethylsilylamide))-manganate(II) in accordance with a formally negative charge assigned to the complex fragment [M{N(SiMe3)2}3]-, which comprises the transition metal). They are formed by addition reactions of LiN(SiMe3)2 and [M{N(SiMe3)2}2] and stabilized by Lewis base/Lewis acid interactions. The results are compared to those of the related "ion-separated" complexes [Li(15-crown-5)][M{N(SiMe3)2}3]. The ate complexes with the lithium atoms connected to the 3d metal atoms manganese, iron, or cobalt via μ2 nitrogen bridges reveal strong 7Li NMR paramagnetic shifts of about -75, 125, and 171 ppm, respectively, whereas the shifts for the lithium ions coordinated by the 15-crown-5 ether are close to zero. The observed trends of the 7Li NMR shifts are confirmed by density-functional theory calculations. The magnetic dc and ac properties display distinct differences for the six compounds under investigation. Both manganese compounds, [LiMn{N(SiMe3)2}3] and [Li(15-crown-5)][Mn{N(SiMe3)2}3], display almost pure and ideal spin-only paramagnetic behavior of a 3d5 high-spin complex. In this respect slightly unexpected, both complexes show slow relaxation behavior at low temperatures under applied dc fields, which is especially pronounced for the ate complex [LiMn{N(SiMe3)2}3]. Dc magnetic properties of the iron complexes reveal moderate g-factor anisotropies with small values of the axial magnetic anisotropy parameter D and a larger E (transversal anisotropy). Both complexes display at low temperatures and, under external dc fields of up to 5000 Oe, only weak ac signals with no maxima in the frequency range from 1 to 1500 s-1. In contrast, the two cobalt complexes display strong g-factor anisotropies with large values of D and E. In addition, in both cases, the ac measurements at low temperatures and applied dc fields reveal two, in terms of their frequency range, well separated relaxation processes with maxima lying for the most part outside of the measurement range between 1 and 1500 s-1.

Electrical spectroscopy of the spin-wave dispersion and bistability in gallium-doped yttrium iron garnet

Yttrium iron garnet (YIG) is a magnetic insulator with record-low damping, allowing spin-wave transport over macroscopic distances. Doping YIG with gallium ions greatly reduces the demagnetizing field and introduces a perpendicular magnetic anisotropy, which leads to an isotropic spin-wave dispersion that facilitates spin-wave optics and spin-wave steering. Here, we characterize the dispersion of a gallium-doped YIG (Ga:YIG) thin film using electrical spectroscopy. We determine the magnetic anisotropy parameters and Gilbert damping from the frequency and linewidth of the ferromagnetic resonance (FMR). Next, we use propagating spin wave spectroscopy in the Damon–Eshbach configuration to detect the small spin-wave magnetic fields of this ultrathin weak magnet over a wide range of wavevectors, enabling the extraction of the exchange constant αex=1.32×10−12 J/m. We observe foldover of the FMR with increasing drive power, leading to frequency shifts of the spin-wave modes and a bistable region in the spin-wave spectra. Our results shed light on isotropic spin-wave transport in Ga:YIG and highlight the potential of electrical spectroscopy to map out the dispersion and bistability of propagating spin waves in magnets with a low saturation magnetization.

Cylindrical nanowire arrays: From advanced fabrication to static and microwave magnetic properties

This article reviews information on arrays of cylindrical magnetic nanowires grown electrochemically inside ordered nanoporous alumina membranes, summarizing some of the most relevant aspects about the advanced synthesis of nanowires and their overall static and microwave magnetic properties. The electrochemical details for the preparation of templates with well-defined hexagonal ordering are addressed focusing on the different anodization methods including mild, hard, pulsed or anodization of aluminum rods. A section follows on the growth of metallic nanowires, either as single element (i.e., Fe, Ni, Co), alloys (i.e., CoFe, CoNi, FeNi) or modulated in composition (i.e., Ferromagnetic/Metal). The static magnetic properties as anisotropy, coercivity and magnetostatic interactions are overviewed with particular emphasis on the influence of magnetocrystalline anisotropy and on the temperature dependence of those properties. The last section is devoted to the ferromagnetic resonance of nanowire arrays of different composition. The dependence of microwave absorption on the orientation of applied field is also a useful tool to determine the magnetic anisotropy parameters and the significance of magnetostatic interactions. The magnetization easy axis can be switched from the nanowire direction to the plane of the membrane as the nanowire filling factor increases or at a compensation temperature, in both cases it derives from the energetic balance of anisotropy and magnetostatic interactions among nanowires. A final subsection is devoted to the spin waves resonance spectra, and the perspectives of applications making use of microwave properties. We expect the article can be useful for researchers interested on the topic and provide a wide overview on the matter to those starting a new research line.

The chain length of anisotropic paramagnetic particles in a rotating field

In this article the maximal length of a chain of paramagnetic particles with magnetic anisotropy in a rotating magnetic field is studied. The theory of paramagnetic particle chains usually assumes that the particles are magnetically isotropic and do not rotate in a rotating field. In experiments it is seen that spherical paramagnetic particles rotate, which can be explained by small magnetic anisotropy. In this article, the maximal chain length is calculated for paramagnetic particles with magnetic anisotropy in a rotating magnetic field. Results show that the maximal chain length as a function of field frequency has the same trend for isotropic magnetic particles and particles with magnetic anisotropy if the field frequency is much higher or much lower than the critical frequency of an individual particle. Initially randomly distributed particles will form chains that will collide and exchange with particles till they obtain a typical chain length. The typical chain length of a small cluster is shorter than the maximal chain length of an isolated chain for the same field frequency. The distribution of chain lengths in a small cluster of chains is narrower for particles with higher magnetic anisotropy. Due to the narrower distribution of chain lengths, particles with magnetic anisotropy can suit better for mass-production. This article will show how magnetic anisotropy parameters of paramagnetic particles influence chain length of chains which form in a rotating magnetic field.

Effect of magnetic anisotropy relaxation on laser-induced magnetization precession in thin galfenol films

The rate and pathways of relaxation of a magnetic medium to its equilibrium following excitation with intense and short laser pulses are the key ingredients of ultrafast optical control of spins. Here we study experimentally the evolution of the magnetization and magnetic anisotropy of thin films of a ferromagnetic metal galfenol (${\mathrm{Fe}}_{0.81}{\mathrm{Ga}}_{0.19}$) resulting from excitation with a femtosecond laser pulse. From the temporal evolution of the hysteresis loops we deduce that the magnetization ${M}_{S}$ and magnetic anisotropy parameters $K$ recover within a nanosecond, and the ratio between $K$ and ${M}_{S}$ satisfies the thermal equilibrium's power law in the whole time range spanning from a few picoseconds to 3 nanoseconds. We further use the experimentally obtained relaxation times of ${M}_{S}$ and $K$ to analyze the laser-induced precession and demonstrate how they contribute to its frequency evolution at the nanosecond timescale.

Topological Hall effect in frustrated B2-ordered Mn0.74Co0.57Al0.69 films

Exploring materials with topological magnetic structures has always been the subject of intense research due to fundamental and technological interests. Here we report the topological Hall effect in the frustrated B2-ordered ${\mathrm{Mn}}_{0.74}{\mathrm{Co}}_{0.57}{\mathrm{Al}}_{0.69}$ thin films. A large topological Hall resistivity of $58.3\phantom{\rule{0.28em}{0ex}}\mathrm{n}\mathrm{\ensuremath{\Omega}}$ cm is found at 300 K. It is shown that a spin reorientation transition occurs around 200 K through the temperature-dependent magnetization and angular-dependent ferromagnetic resonance measurements. Using the obtained magnetic anisotropy parameters, we perform the micromagnetic simulations to simulate the formation and evolution of topological magnetic structures with temperature, demonstrating the influence of the higher-order magnetic anisotropies. This work enriches the variety of materials exhibiting topological Hall effect and helps to clarify the mechanism of new emergent topological features in magnetic materials.

Magnetic Anisotropy in a Cubane-like Ni4 Complex: An Ab Initio Perspective.

Magnetic anisotropy, in the absence of an external magnetic field, relates to the degeneracy lift of energy levels. In the standard case of transition metal complexes, this property is usually modeled by an anisotropic spin Hamiltonian and one speaks of "zero-field splitting" (ZFS) of spin states. While the case of mononuclear complexes has been extensively described by means of ab initio quantum mechanical calculations, the literature on polynuclear complexes studied with these methodologies is rather scarce. In this work, advanced multiconfigurational wave function theory methods are applied to compute the ZFS of the ground S = 4 state of an actual tetranickel(II) complex, displaying a magnet behavior below 0.5 K. First, the isotropic couplings are computed in the absence of the spin-orbit coupling operator, in the full complex and also in clusters with only two active nickel(II) centers, confirming the occurrence of weak ferromagnetic couplings in this system. Second, the single-site magnetic anisotropies are computed on a cluster bearing only one active nickel(II) site, showing that the single-site anisotropy axes are not oriented in an optimal fashion for generating a large uniaxial molecular anisotropy. Furthermore, the possibility for involving only a few local orbital excited states in the calculation is assessed, actually opening the way for a consistent and manageable treatment of the ZFS of the ground S = 4 state. Third, multiconfigurational calculations are performed on the full complex, confirming the weak uniaxial anisotropy occurring for this state and also, interestingly, revealing a significant contribution of the lowest-lying orbitally excited S = 3 states. Overall, by comparison with the experiment, the reported results question the common habit of using only one structure, in particular derived from a crystallography experiment, to compute magnetic anisotropy parameters.

Ferromagnetic resonance study on the influence of the electrolytic bath acidity on the magnetic anisotropy of Ni nanowires

In this work, a ferromagnetic resonance study on the influence of the electrolytic bath acidity on the magnetic anisotropy and hardness parameter of arrays of 50 nm diameter Ni nanowires in porous alumina membranes, is reported. Fine tuning the effective magnetic anisotropy of the arrays has been achieved by progressively changing the nanowires microstructure from polycrystalline textured to single-crystalline as the electrolyte acidity is reduced. The micro-structural analysis carried out by X-ray diffraction and high resolution transmission electron microscopy has revealed that a preferred crystal texture is not a sufficient condition for the enhancement of the magnetic anisotropy. Instead, a correlation between the increase of crystallite size and quality, and the increase of both the magnetic anisotropy and hardness parameter has been shown. Ferromagnetic resonance and alternating gradient magnetometry experiments have shown that no additional magnetic contributions take place in Ni NWs grown from highly acidic electrolytes (pH 1.6), whereas a significant additional anisotropy contribution progressively appears as the electrolyte acidity is reduced (pH 5.0). Besides the careful adjustment of electrodeposition conditions, achieving a very long length for the nanowires is also a key requirement to have a precise control on the effective magnetic anisotropy energy, which can be fine tuned in the wide range from 64-167 kJ·m−3 as a result of an energy enhancement of magnetoelastic origin. Ferromagnetic resonance measurements have demonstrated that nanocomposites based on arrays of nanowires made of low cost and abundant elements like Ni exhibit hardness parameters in the range 0.47–0.75 within the semihard region, where those with κ>0.5 are suitable for permanent magnet applications. These features make arrays of low diameter Ni nanowires very appealing for their use in the development of agile microwave and spintronic devices.