Annealing effect on structural, microstructural and magnetic properties of nanocrystalline Er-Co-B alloys for permanent magnet applications

Rachid, F.Z.; Omari, L.H.; Yamkane, Z.; Lassri, H.; Derkaoui, S.; Nouri, K.; Bouzidi, W.; Bessaïs, L.

doi:10.1016/j.matchemphys.2019.02.036

Cited by 8 publications

(5 citation statements)

References 26 publications

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“…Based on the isothermal magnetizations, we determined the thermal variation of the magnetic entropy change -ΔS of Er 0.98 , 0.02 Co 2 via Maxwell's relation (7) as posted in figure 10(a). Increasing the applied magnetic field from 1 up to 7 T, a considerable MCE was detected in this system.…”

Section: Resultsmentioning

confidence: 99%

“…This universality class depends on the values of the critical exponents characterizing the phase transition. To understand the nature of this transition, we have discussed the critical behavior, predicting the existence of a universality class of the prepared system [7][8][9]. Scaling curves extracted from the isotherms of magnetizations around the critical temperature of transition have been investigated to derive the critical exponents of the magnetization β, for the temperature dependence of the spontaneous magnetization below Curie Temperature (T C ), and γ for the magnetic susceptibility, and δ for the magnetic isotherm at T C .…”

Section: Introductionmentioning

confidence: 99%

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Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

Hamdi¹,

Smari²,

Bajorek³

et al. 2020

Phys. Scr.

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Magnetic refrigeration is a promising energy efficient and environmentally friendly refrigeration technology. The major problem in magnetic refrigeration is to find working materials with a large magnetocaloric effect (MCE) in different temperatures regions. MCE is the reversible temperature change of a magnetic materials upon the application or removal of a magnetic field. Nanoscale magnetic materials are good candidates for magnetic refrigeration due to a presence of a large MCE in the superparamagnetic system and reduced hysteresis losses. The critical behavior of Er0.98□0.02Co2 intermetallic system has been investigated via isothermal magnetizations around its ferromagnetic-paramagnetic (FM-PM) transition at Curie temperature TC = 62 K. This study was performed through different methods; Arrott-Noakes technique, Kouvel-Fisher analysis, and critical isotherms procedure. All these models could not explain the behavior of the studied system, which suggest that it belongs to an unconventional critical behavior. The critical exponents of the magnetization β, for the temperature dependence of the spontaneous magnetization below Curie Temperature (TC), and γ for the magnetic susceptibility, and δ for the magnetic isotherm at TC were calculated. Based on Modified Arrott plots; Er0.98□0.02Co2 gives TC = 62.57 K ± 0.01 K with β = 0.68 ± 0.005 and TC = 62.59 K ± 0.01 K with γ = 0.88 ± 0.008. Using Kouvel-Fisher technique, we get TC = 62.66 K ± 0.06 K with β = 0.71 ± 0.01 and TC = 62.54 K ± 0.02 K with γ = 0.90 ± 0.06. The extracted value of δ from the critical isotherms and the Widom scaling relation are so close confirming that the obtained critical exponents are suitable and accurate within experimental error values. With 536.45 J kg−1 at 5 T of relative cooling power, Er0.98□0.02Co2 is very promising as magnetic refrigerant.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

Hamdi¹,

Smari²,

Bajorek³

et al. 2020

Phys. Scr.

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“…It depends on the values of the critical exponents defining the phase transition (FM → PM). To appreciate the type of this transition, we have addressed the critical behavior in LT-1h, LT-3h, and LT-6h samples [61][62][63]. We relied on the isotherms of magnetizations around T C to extract the critical exponents of the magnetization; noting 'β' to design the temperature dependence of the spontaneous magnetization below T C , 'γ' to express the magnetic susceptibility, and 'Δ' for the magnetic isotherm at T C obeying the Widom scaling law: It's meriting to notice that the effective internal magnetic field H int , which was used to define the various critical exponents, was corrected by a demagnetization factor (D) with; H int = H app -DM; D presents the demagnetization factor deduced from magnetizations as a function of magnetic fields measurements at the low field linear response regime at very low temperature.…”

Section: Magnetocaloric Effect Studymentioning

confidence: 99%

La_0.6X_0.1Te_0.3MnO₃ system with significant refrigerant capacity at low magnetic field and double magnetic entropy change peaks: effect of ball-milling time on physical and critical behaviors

et al. 2023

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We have investigated the ball-milling time effect on different physical properties of La0.6◻0.1Te0.3MnO3 system (LT) milled for 1 hour (LT-1h), 3 hours (LT-3h), and 6 hours (LT-6h). According to Williamson-Hall method, as the ball-milling duration is increased, the material's crystallite size decreases from approximately 145 to 99 nm for LT-1h and LT-6h, respectively. Electronic study was also investigated. The Zero-Field-Cooling and Field-Cooling (ZFC/FC) magnetization measurements illustrated that all the systems are presenting a ferromagnetic to paramagnetic phase transition around Curie temperature (TC). This transition is around 176, 182, and 183 K accompanied by a decrease in the magnitude in both ZFC and FC data. Thus, increasing the ball-milling time of the sample leads to the elevation of TC and does not enhance the magnitude of the magnetization the fact that it affects the magnetic interactions between atoms. By increasing the ball-milling duration, the proportion of homogeneity is increased, and the material becomes slightly more resilient, according to the Curie-Weiss law. Additionally, it is accompanied with an increase in coercivity and a decrease in the saturation magnetization and remanence. Based on the AC-susceptibility, raising the ball-milling time facilitates the appearance of a spin-glass (SG) state. The relative cooling power (RCP) value in the LT-1h sample at 2 T is 108 % (211.758 J/kg) compared to that of the Gd at 2 T. Consequently, the LT sample could be a permanent magnet in a magnetic refrigerator. Noting that raising the ball-milling time weakens the RCP. Both LT-1h and LT-3h systems are belonging to the tricritical mean field model. However, for LT-6h, the model changed and the best one became the 3D-Ising model. Hence, the ball-milling time influences also the universality class.

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“…Samarium (Sm)-cobalt (Co) permanent magnetic material stands out as an outstanding hard magnet [1]. The optimization of the magnetic performance in Sm-Co alloys often involves the addition of elements such as copper (Cu), iron (Fe), zirconium (Zr), and boron (B) [2][3][4][5]. However, the microstructure and magnetic properties of the alloy are significantly affected by the Co content.…”

Section: Introductionmentioning

confidence: 99%

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Fern,

Liu,

Chang

et al. 2023

Materials

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Co60Fe20Sm20 thin films were deposited onto glass substrates in a high vacuum setting. The films varied in thickness from 10 to 50 nm and underwent annealing processes at different temperatures: room temperature (RT), 100, 200, and 300 °C. Our analysis encompassed structural, magnetic, electrical, nanomechanical, adhesive, and optical properties in relation to film thickness and annealing temperature. X-ray diffraction (XRD) analysis did not reveal characteristic peaks in Co60Fe20Sm20 thin films due to insufficient growth-driving forces. Electrical measurements indicated reduced resistivity and sheet resistance with increasing film thickness and higher annealing temperatures, owing to hindered current-carrier transport resulting from the amorphous structure. Atomic force microscope (AFM) analysis showed a decrease in surface roughness with increased thickness and annealing temperature. The low-frequency alternating current magnetic susceptibility (χac) values increased with film thickness and annealing temperature. Nanoindentation analysis demonstrated reduced film hardness and Young’s modulus with thicker films. Contact angle measurements suggested a hydrophilic film. Surface energy increased with greater film thickness, particularly in annealed films, indicating a decrease in contact angle contributing to this increase. Transmittance measurements have revealed intensified absorption and reduced transmittance with thicker films. In summary, the surface roughness of CoFeSm films at different annealing temperatures significantly influenced their magnetic, electrical, adhesive, and optical properties. A smoother surface reduced the pinning effect on the domain walls, enhancing the χac value. Additionally, diminished surface roughness led to a lower contact angle and higher surface energy. Additionally, smoother surfaces exhibited higher carrier conductivity, resulting in reduced electrical resistance. The optical transparency decreased due to the smoother surface of Co60Fe20Sm20 films.

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Annealing effect on structural, microstructural and magnetic properties of nanocrystalline Er-Co-B alloys for permanent magnet applications

Cited by 8 publications

References 26 publications

Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

La_0.6X_0.1Te_0.3MnO₃ system with significant refrigerant capacity at low magnetic field and double magnetic entropy change peaks: effect of ball-milling time on physical and critical behaviors

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

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Annealing effect on structural, microstructural and magnetic properties of nanocrystalline Er-Co-B alloys for permanent magnet applications

Cited by 8 publications

References 26 publications

Unconventional critical behavior of the magnetic refrigerant system Er0.98□0.02Co2 around its ferromagnetic-paramagnetic transition

Unconventional critical behavior of the magnetic refrigerant system Er0.98□0.02Co2 around its ferromagnetic-paramagnetic transition

La0.6X0.1Te0.3MnO3 system with significant refrigerant capacity at low magnetic field and double magnetic entropy change peaks: effect of ball-milling time on physical and critical behaviors

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Contact Info

Product

Resources

About

Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

Unconventional critical behavior of the magnetic refrigerant system Er_0.98□_0.02Co₂ around its ferromagnetic-paramagnetic transition

La_0.6X_0.1Te_0.3MnO₃ system with significant refrigerant capacity at low magnetic field and double magnetic entropy change peaks: effect of ball-milling time on physical and critical behaviors