FeCo Phase Research Articles

Development of nanocrystallized magnetoelastic sensors with self-biased effect and improved mass sensitivity

The growing demand for cost-effective and wireless sensing technologies requires the development of simple, efficient and optimized sensors able to accurately detecting external agents. Magnetoelastic resonators represent an alternative to the traditional sensing systems, able to combine all the previously cited factors. Several studies have focused on increasing their sensitivity, in order to make it closer to the market. The present study explores thermal treatments as a novel approach to enhance the sensitivity of magnetoelastic resonators, focusing on the positive impact of crystallization processes induced in magnetoelastic platforms. The experimental results confirm an enhancement of resonant frequency and quality factor of the magnetoelastic platforms as treatment temperature increases. Particularly, the sensor annealed at 550 °C shows an increase of the resonant frequency value of 45 % with respect to the as-quenched platform, being that increase of around 1700 % for the quality factor. In addition, the nanocrystallization induction leads to a self-biased resonance, consequence of the intrinsic magnetization resulting from the crystallization in Fe2B and FeCo phases. Further, the study shows the importance of stability in resonant frequency, emphasizing the potential of the 550 °C-annealed platform for mass sensor applications. Gold deposition experiments reveal the enhanced sensitivity of the sensor annealed at 550 °C of 40 % compared to the as-quenched sensor, as well as an increase of 38 % on its accuracy. These findings represent a significant step forward in the development of magnetoelastic-based mass sensors, highlighting the pivotal role of thermal treatments in optimizing sensitivity for practical and efficient external agents detection systems.

FeCo@hydrochar nanocomposites as efficient peroxymonosulfate activator for organic pollutant degradation.

Sulfate radical-based advanced oxidation processes (SR-AOPs) are renowned for their exceptional capacity to degrade refractory organic pollutants due to their wide applicability, cost-effectiveness, and swift mineralization and oxidation rates. The primary sources of radicals in AOPs are persulfate (PS) and peroxymonosulfate (PMS) ions, sparking significant interest in their mechanistic and catalytic aspects. To develop a novel nanocatalyst for SR-AOPs, particularly for PMS activation, we synthesized carbon-coated FeCo nanoparticles (NPs) using solvothermal methods based on the polyol approach. Various synthesis conditions were investigated, and the NPs were thoroughly characterized regarding their structure, morphology, magnetic properties, and catalytic efficiency. The FeCo phase was primarily obtained at [OH-] / [Metal] = 26 and [Fe] / [Co] = 2 ratios. Moreover, as the [Fe]/[Co] ratio increased, the degree of xylose carbonization to form a carbon coating (hydrochar) on the NPs also increased. The NPs exhibited a spherical morphology with agglomerates of varying sizes. Vibrating-sample magnetometer analysis (VSM) indicated that a higher proportion of iron resulted in NPs with higher saturation magnetization (up to 167.8 emu g-1), attributed to a larger proportion of FeCo bcc phase in the nanocomposite. The best catalytic conditions for degrading 100ppm Rhodamine B (RhB) included 0.05g L-1 of NPs, 2mM PMS, pH 7.0, and a 20-min reaction at 25°C. Notably, singlet oxygen was the predominant specie formed in the experiments in the SR-AOP, followed by sulfate and hydroxyl radicals. The catalyst could be reused for up to five cycles, retaining over 98% RhB degradation, albeit with increased metal leaching. Even in the first use, dissolved Fe and Co concentrations were 0.8 ± 0.3 and 4.0 ± 0.5mg L-1, respectively. The FeCo catalyst proved to be effective in dye degradation and offers the potential for further refinement to minimize Co2+ leaching.

Phase decomposition of AlCrFeCoNiCu0.5 HEA thin films by vacuum annealing

The most attractive advantages of high entropy alloy (HEA) thin films are their excellent properties, such as high strength and high corrosion and oxidation resistance, with a lower material cost. However, the thermal stability of the HEA thin films is always controversial. This is critical since the thermal stability of metals and alloys is closely related to the material's performance at high temperatures and also determines the application field of the material. The question of how will the nanocrystalline high entropy alloy thin film perform in terms of thermal stability needs to be clarified urgently. In this research, the thermal stability of AlCrFeCoNiCu0.5 HEA thin film fabricated by cathodic arc deposition was investigated at 500 °C as a function of time during vacuum annealing. X-Ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM) and Transmission Kikuchi Diffraction (TKD) were applied to analyze the chemistry and microstructure of HEA thin films in detail. The results showed that there was no obvious change in the elemental compositions of the films after annealing, but the elemental distribution of the annealed films was different from the as-deposited film, especially at the film surface and film-substrate interface for the 24 h-annealed sample. The existence of the FeCo phase with B2 structure was a significant sign to demonstrate that the spinodal decomposition occurred in the single face-centered-cubic (FCC) phase matrix of the film during annealing. Simultaneously, the segregation of Cu and Cr near the film-substrate interface and the penetration of Ni and Cu towards the Si substrate were clearly observed. These unusual phenomena indicated that the thermal stability of HEA was not always excellent. Also, it was noticed that a few Kirkendall voids forming at the film-substrate interface after 24 h of annealing would affect the adhesion of the film. Additionally, heat recovery and recrystallization were achieved by 500 °C annealing, which were confirmed by the decrease of lattice parameter and the increase of grain size in the 24 h-annealed thin film. Furthermore, the hardness and elastic modulus of the thin films before and after annealing were measured by nanoindentation. The results showed all the thin films exhibited excellent mechanical properties, and the optimal hardness and elastic modulus of 7.7 ± 0.3 GPa and 183.9 ± 4.4 GPa were obtained after 3 h-annealing.

The effect of ternary additions on the structural and mechanical properties of B2 phase FeCo magnetic alloy

FeCo alloy constitutes an important class of soft-magnetic materials with a wide range of technological applications. This class of materials offers exceptional magnetic properties due to their rare combination of good properties like high mechanical strength, and high saturation magnetization. Fortunately, this alloy has good magnetic properties, but shows low levels of ductility at room temperature. This study intends to use density functional theory (DFT), to understand how ternary alloying with Pd and Mn can improve the ductility of B2 FeCo system. We probe the relationship between stability and composition of the ternary Fe50Co50−xMx (M = Pd, Mn) with different M content. Furthermore, the study also investigates how ternary alloying affects the stability of the B2 FeCo alloy. There is a significant enhancement of ductility with Mn addition than Pd ternary addition. It is noteworthy that small composition of Pd (< 10 at.%) does not compromise the valuable properties of FeCo. The findings suggest that Fe50Co50−xMx alloys can be used for the future development of magnetic components with good strength.Graphical abstractThe effect of ternary additions on the structural and mechanical properties of B2 phase FeCo magnetic alloy.

Enhanced strength of AlCoCrCu0.5FeNi high entropy alloy thin films reinforced by multi-phase hardening and nanotwins

High entropy alloy (HEA) thin films have become increasingly popular because they exhibit favorable properties but with lower material consumption. Here, this research demonstrates that annealing of AlCoCrCu0.5FeNi thin films results in multiphase hardening and the formation of nanotwins. HEA thin films were atmospherically annealed at different temperatures (300 – 700 °C) for 5 h. A thin dense oxide layer consisting of Al2O3 and Cr2O3 appeared at the top surface of the 700 °C annealed film. This oxide layer endows the HEA thin film with excellent antioxidant properties. As such, vacuum and inert gas might not be required for HEAs annealing process at up to 700 °C. A phase transformation was observed in the film annealed at 700 °C for 5 h from X-ray diffraction patterns. Results from transmission Kikuchi diffraction and energy dispersive X-ray spectroscopy mapping indicated the formation of three new phases, including the FeCo phase, Cr-rich phase and Cu nano-clusters. Variations also happened in HEA FCC matrix where two types of texture existed in the HEA FCC grains i.e., {012} <110> and {112} <110>. Of particular interest was that high-resolution transmission electron microscopy revealed a high density of annealing nanotwins among the HEA FCC grains, including lamellar and co-axial twins. The influence of these structural phenomena on mechanical properties was evaluated. The results showed that the hardness and modulus of 700 °C annealed HEA thin film increased by 25% and 24% to 8.4 ± 0.2 GPa and 149.4 ± 6.1 GPa when compared to the properties of as-deposited films.

Microstructure and physical properties of dual-phase soft magnetic Fe-Co-Ti-Ge alloys

Soft magnetic materials play a crucial role in determining the efficient operation of power electronics and electrical machines. Recently, compositionally complex alloys have shown to offer promising magnetic properties that can be engineered by composition and microstructure. In this work, we investigate the microstructures and physical properties of novel dual-phase Fe-Co-Ti-Ge alloys by introducing ferromagnetic Heusler-type phases into a disordered ferromagnetic matrix. The microstructure of three alloys is studied in the as-cast and homogenized state and is primarily composed of a Fe-Co BCC-A2 matrix phase and Fe-Co-Ti-Ge-based L21-ordered Heusler phases. A Ti-Ge-rich phase is observed to form in the Fe50Co20Ti10Ge20 (at%) alloy. The physical and magnetic properties of these alloys show a good combination of high electrical resistivity (202 – 252 µΩ‧cm), high Curie temperature (> 1000 K), moderate saturation magnetization (74 – 99 A‧m2/kg) and coercivity (390 – 1099 A/m). The phase arrangement, morphology and composition of the BCC-A2 and L21-Heusler phases are responsible for the observed differences in magnetic properties, which can be further tuned by tailoring the microstructure.

Reactive ball-milling synthesis of Co-Fe bimetallic catalyst for efficient hydrogenation of carbon dioxide to value-added hydrocarbons

Catalytic hydrogenation of CO2 using renewable hydrogen not only reduces greenhouse gas emissions, but also provides industrial chemicals. Herein, a Co-Fe bimetallic catalyst was developed by a facile reactive ball-milling method for highly active and selective hydrogenation of CO2 to value-added hydrocarbons. When reacted at 320 °C, 1.0 MPa and 9600 mL h−1 gcat−1, the selectivity to light olefin (C2=–C4=) and C5 + species achieves 57.3% and 22.3%, respectively, at a CO2 conversion of 31.4%, which is superior to previous Fe-based catalysts. The CO2 activation can be promoted by the CoFe phase formed by reactive ball milling of the Fe-Co3O4 mixture, and the in-situ Co2C and Fe5C2 formed during hydrogenation are beneficial for the C–C coupling reaction. The initial C–C coupling is related to the combination of CO species with the surface carbon of Fe/Co carbides, and the sustained C–C coupling is maintained by self-recovery of defective carbides. This new strategy contributes to the development of efficient catalysts for the hydrogenation of CO2 to value-added hydrocarbons.

Amorphous/nanocrystalline coating on 45 steel prepared by laser processing of pre-electrodeposited coating

In this study, a composite electroplating method was used to improve the traditional feeding processes in laser cladding. First, 45 steel was pre-coated with a mixture of Fe-based amorphous powders and Co via electrodeposition. Then, laser cladding was carried out to obtain an amorphous–nanocrystalline coating. The morphology, hardness, wear resistance, and corrosion resistance of the coating were characterized, and the phase evolution was studied. Benefiting from the superior glass forming ability and fast solidification, amorphous phase and nanocrystals were formed in the coating. The coating was predominantly made up of CoFe and Fe3Co crystalline phases, with a minor quantity of complex amorphous phases. The amorphous–nanocrystalline coating demonstrated exceptional surface properties. It had a notable hardness of 10.88 ± 0.32 GPa, which was higher than that of 45 steel by 4.3 times. Its wear rate, corrosion current density (Icorr), and polarization resistance were 0.343 ± 0.037 (37.5 % lower than that of 45 steel) and 1.385 ± 0.193 μA⋅cm−2 (1/8 times that of the matrix), and 13,992.92 ± 1165.9 Ω⋅cm2 (nine times that of 45 steel), respectively.

Magnetic bond-order potential for iron-cobalt alloys

For large-scale atomistic simulations of magnetic materials, the interplay of atomic and magnetic degrees of freedom needs to be described with high computational efficiency. Here we present an analytic bond-order potential (BOP) for iron-cobalt, an interatomic potential based on a coarse-grained description of the electronic structure. We fitted BOP parameters to magnetic and non-magnetic density functional theory (DFT) calculations of Fe, Co, and Fe-Co bulk phases. Our BOP captures the electronic structure of magnetic and nonmagnetic Fe-Co phases. It provides accurate predictions of structural stability, elastic constants, phonons, point and planar defects, and structural transformations. It also reproduces the DFT-predicted sequence of stable ordered phases peculiar to Fe-Co and the stabilization of B2 against disordered phases by magnetism. Our Fe-Co BOP is suitable for atomistic simulations with thousands and millions of atoms.

Microstructure evolution of hot-deformed SmCo-based nanocomposites induced by thermo-mechanical processing

• The two-stage phase transition occurred successively, accompanied by grain growth. • Texture formed in 1:5H phase, not in 2:17R phase in SmCo-based nanocomposites. • Proposed a new strategy for forming c-axis textures in nanocomposites. Nanocomposite permanent magnets have ultra-high theoretical magnetic energy products, due to coupling of the soft/hard magnetic phases, inciting strict microstructural requirements. In this study, the microstructure evolution, including the phase transition, morphological changes, and texture formation, of hot-deformed SmCo-based nanocomposites under thermal–stress–strain coupling was characterized to determine a possible strategy for achieving high performance. The SmCo 5 /α-Fe nanocomposites precursor contained fine and dispersed Sm(Fe, Co) 5 and Fe-Co grains and exhibited a two-stage phase transformation accompanied by grain growth. In the early stage of deformation at relatively low temperature, the adjacent Sm(Co, Fe) 5 and Fe-Co phase formed the Sm 2 (Co, Fe) 17 -H phase, which was stable only with small grain sizes. In the high-temperature deformation stage, the Sm 2 (Co, Fe) 17 -H phase transformed into the Sm 2 (Co, Fe) 17 -R phase with large grain sizes. In addition, the strong c -axis texture formed in the Sm(Co, Fe) 5 phase but not in the Sm 2 (Co, Fe) 17 -R phase. Subsequently, the phase transition process and texture formation mechanism were systematically analyzed by transmission electron microscopy. The initiation of a slip system and/or preferential grain growth explained the formation of texture under the action of uniform stress and strain and assisted by dispersed Sm-rich nanograins. The Sm 2 (Co, Fe) 17 -R grains with poor orientations and large grain sizes did not achieve magnetic hardening, which also damage the magnetic properties. According to the results of this work, we also presented a new strategy to prepare high-performance SmCo-based nanocomposites magnets.

Atom-scale characterization and 2D/3D modeling of carbides and Fe Co phases in Stellite 6 laser clad coating after aging treatment

This study applied various aging treatment (AT) times at 650 °C in Stellite 6 laser cladding layer, conducted the atom-scale characterization of stacking faults (SFs) and nanoscale M23C6 carbides, described the martensitic transformation of γ → ε, and discussed on the growth mechanism of FeCo and M23C6 phases by 3D/2D modeling. Results show the formation of three distinct regions relative to Fe diffusion, namely, interfacial layer with FeCo and M23C6 phases, Fe diffusion-affected zone with FexCoy distribution at the edge of M23C6 carbides along grain boundary, and Fe diffusion-unaffected zone with abundant carbide precipitation and SF generation. In addition, the formation of M23C6 and FeCo phases conformed to dynamics and thermodynamics. Suzuki effect influence the nanoscale carbides with profile and growing direction of [121¯] and [110], respectively, and martensite transformation occurred on (1¯11¯)γ parallel to (0002)ε as characterized by 2D modeling and HRTEM. The microhardness of surfacing layer was measured in diverse zones, and the results present that AT softened the interfacial layers but increased the hardness of Fe diffusion-affected zones and Fe diffusion-unaffected zones.

Structural features of near equiatomic FeCo-2V semi-hard magnetic alloy prepared by MIM technology

The structural properties of a magnetically semi-hard near equiatomic FeCo-2wt%V (FeCoV) alloy produced by Powder Injection Moulding (PIM) (option by fine metal powder - Metal Injection Moulding (MIM) technology) were investigated in this paper. Starting granulate was prepared by mixing FeCoV powder with a low-viscosity binder. After injection, the green samples were first treated with a solvent and then thermally with the same aim of removing the binder. MIM technology was completed by high-temperature sintering for 3.5 hours at temperatures from 1370 OC to 1460 OC in a hydrogen atmosphere, which provides the necessary magnetic and mechanical characteristics. The influence of sintering temperature was investigated concerning the aspects of the processes of structural transformation by the methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The appearance of an intense diffraction peak of the ?'-FeCo phase (crystal structure type B2) was registered for all investigated samples. Structural parameters particle size Dmax, Feret X, and Feret Y exhibit constant increase with increase of sintering temperature.

Abnormal notch brittleness induced by short-range ordering in low-cobalt iron-cobalt alloys under tensile and impact loading: A combined experimental and molecular dynamics simulation study

According to the binary Fe-Co phase diagram, Fe-21.5/23 wt% Co alloys undergo an order-disorder transition in the temperature range of 430–470 °C. Above the order-disorder temperature, Fe-21.5/23 wt% Co alloys are generally considered as disordered solid solutions with excellent ductility and toughness. In this work, short-range ordered (SRO) structures in Fe-21.5 wt% Co alloy quenched from α phase region were directly observed via scanning transmission electron microscope (STEM). SROs are mainly the B2 structure, with a very small amount of L60 Fe3Co structure. The mechanisms of SRO-induced notch brittleness were systematically investigated by experiments and molecular dynamics (MD) simulations. Under tensile loading, SROs change slip mode from cross slip to planar slip, which significantly leads to the strengthening effects and large work hardening rates. For the notch tensile tests, different notch depths were set to investigate the effects of SROs on the notch brittleness. The Fe-23 wt% Co samples quenched from 550 °C were surprisingly found to exhibit the notch brittleness induced by SROs. Under impact loading, SROs significantly lead to impact brittleness with the cleavage fracture. MD results of notch tensile and impact tests showed that SRO-induced poor dislocation and twinning plasticity leads to larger concentrated stresses and stress concentration factor near the notch, directly resulting in the easier nucleation and rapid propagation of intergranular and intracrystalline microcracks. Our findings suggest that SRO-induced notch brittleness must be considered in engineering applications for the low-cobalt iron-cobalt alloys.

Molecular dynamics study of FeCo phase transitions and thermal properties based on an improved 2NN MEAM potential

A semi-empirical potential in line with the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism has been improved for the Fe–Co interactions intended to reproduce the different thermal phases stability. Fundamental structural and elastic properties are correctly reproduced. Point defects have been included in the fitting to improve the thermodynamic characteristics. Molecular dynamics simulations using this potential predict melting temperatures which aligns with experimental data and is the first potential showing a temperature-induced B2 to L10/hcp transformation. A disorder transformation is observed by diffusing vacancies at different temperatures and quantified by the long-range order parameter. The potential is also applied to thin films of the metastable L10 structure by using a face-centered cubic buffer, which can predict the good stability and energetical results comparable to ab initio calculations. The potential proves useful to study the thermal effects of different FeCo phases in bulk and multilayer films.

Exchange bias and exchange spring in CoFe2O4/FeO/CoFe nanocomposites

A series of CoFe2O4/FeO/CoFe nanocomposites was prepared by reducing cobalt ferrite nanoparticles under the mixed gas of Ar (95%) and H2 (5%) at 450 °C for different times, and the effects of exchange bias and exchange spring have been observed. X-ray diffraction and Mössbauer spectroscopy demonstrate CoFe2O4/FeO/CoFe nanocomposites are obtained when the reduction time exceeds 0.5 h, and the concentrations of CoFe2O4 and FeO decrease, accompanied by the increase of CoFe on extending the reduction time. The field emission scanning electron microscope and transmission electron microscope images show the spherical CoFe2O4, FeO, and CoFe nanoparticles with the average sizes about 17.0 nm are randomly distributed with a certain degree of agglomeration. Magnetic measurements indicate there is a strong exchange bias behavior between the CoFe2O4 and FeO nanoparticles in the sample reduced for 0.5 h with an exchange bias field being 1161.4 Oe at 50 K, and a good exchange spring effect between CoFe2O4 and CoFe phases in the sample reduced for 1.5 h with saturation magnetization, remnant magnetization, and coercivity at 300 K being 121.33 emu/g, 41.90 emu/g, and 802.4 Oe. These results are important not only for understanding the exchange-coupling interaction in the reduction process of cobalt ferrite but also for their application in spin-valve devices.

Atom-Scale Characterization and 2d/3d Modeling of Carbides and Fe-Co Phases in Stellite 6# Laser Cladding During Aging Treatment

Atom-Scale Characterization and 2d/3d Modeling of Carbides and Fe-Co Phases in Stellite 6# Laser Cladding During Aging Treatment

Molecular Dynamics Study of Feco Phase Transitions and Thermal Properties Based on an Improved 2nn Meam Potential

Molecular Dynamics Study of Feco Phase Transitions and Thermal Properties Based on an Improved 2nn Meam Potential

Ordered structure and solute-suppressed atomic ordering in iron-cobalt alloys

The slowly cooled Fe-25 wt% Co alloys generally suffer from poor ductility due to the atomic ordering. Combining DFT calculations and experiments, ordered L60-Fe3Co structure was first demonstrated to crystallize in the slowly cooled ∼ 25 wt% Co alloys and lead to brittleness. The stable existence of L60-Fe3Co structure is of great significance to further understand the binary Fe-Co phase diagram. Metal elements (e.g. V and Nb) are generally added into FeCo alloy to improve ductility and workable ability. The toughening mechanism of these solutes is mainly realized by suppressing atomic ordering. The reduced antisite defect energies by V and Nb additions lowers the maximum degree of order and antiphase boundary (APB) energies. The key to suppress atomic ordering is reducing antisite defect energy or site-exchange energy. A comprehensive theoretical understanding on the mechanism of suppressing atomic ordering is helpful to further find alloying elements which simultaneously improve mechanical and magnetic properties for Fe3Co or other ordered alloys.

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere.

Thermal treatment is a post-synthesis treatment that aims to improve the crystallinity and interrelated physical properties of as-prepared materials. This process may also cause some unwanted changes in materials like their oxidation or contamination. In this work, we present the post-synthesis annealing treatments of the amorphous Fe1−xCox (x = 0.25; 0.50; 0.75) Wire-like nanochains performed at 400 °C in two different atmospheres, i.e., a mixture of 80% nitrogen and 20% hydrogen and argon. These processes caused significantly different changes of structural and magnetic properties of the initially-formed Fe-Co nanostructures. All of them crystallized and their cores were composed of body-centered cubic Fe-Co phase, whereas their oxide shells comprised of a mixture of CoFe2O4 and Fe3O4 phases. However, the annealing carried out in hydrogen-containing atmosphere caused a decomposition of the initial oxide shell layer, whereas a similar process in argon led to its slight thickening. Moreover, it was found that the cores of thermally-treated Fe0.25Co0.75 nanochains contained the hexagonal closest packed (hcp) Co phase and were covered by the nanosheet-like shell layer in the case of annealing performed in argon. Considering the evolution of magnetic properties induced by structural changes, it was observed that the coercivities of annealed Fe-Co nanochains increased in comparison with their non-annealed counterparts. The saturation magnetization (MS) of the Fe0.25Co0.75 nanomaterial annealed in both atmospheres was higher than that for the non-annealed sample. In turn, the MS of the Fe0.75Co0.25 and Fe0.50Co0.50 nanochains annealed in argon were lower than those recorded for non-annealed samples due to their partial oxidation during thermal processing.

The role of FeCo and FeCoCr nanowires array on the formation of single phase bi-magnets

Nanowire (NWs) arrays of FeCo and FeCoCr were prepared by AC pulsed electrodeposition embedded into an alumina template. They were then employed as an underlayer to provide the dot array of cobalt ferrite thin films. Highly ordered arrays of NWs with the diameter of 30 nm and length of 10 µm were fabricated and then annealed in various environments. The cobalt ferrite thin films were deposited by the sputtering approach with the almost constant thickness of 70 nm as the hard magnetic phase. The combination of FeCo and cobalt ferrite could provide an exchange spring magnet with the magnetic coupling feature. X-ray diffraction (XRD) patterns of the NW arrays indicated the formation of the body centered cubic (bcc) FeCo phase with [110] texture. Field emission electron microscopy (FESM) equipped by EDS also characterized the morphological features and elemental composition. Magnetization and coercivity of NWs were examined using the vibrating sample magnetometer. The maximum coercivity of NWs array is 2950 Oe which is related to H2 annealing FeCo NWs array. The magnetization reversal process of the as-deposited and annealed FeCo and FeCoCr NWs arrays was performed by angular dependence coercivity and squareness. Further, FORC diagrams indicated an interacting single domain behavior for as-deposited FeCo NWs and a weakly-interacting single domain state for the annealed samples. The morphological and structural features of cobalt ferrite were also studied by XRD, FE-SEM and AFM techniques. It was found that the cobalt ferrite dot array with a uniform chemical composition and structure was formed. The inter-diffusion of atoms between underlayer and thin films was confirmed by EDS. The maximum coercivity of the nanocompsite was 5800 Oe that is obtained for FeCoCr underlayer with argon annealing. The VSM analysis showed that sufficient exchange coupling was formed by using the FeCoCr underlayer in hydrogen annealing, while argon annealing provided a kink in the hysteresis loops. The obtained nanocomposites could be, therefore, considered as the potential candidate for use in the exchange spring magnet.