Low Temperature Magnetic Behavior of Ni-Fe-Al-B Shape Memory Alloys: Magnetic Susceptibility and Mössbauer Spectra.

1994 ◽  
Vol 360 ◽  
Author(s):  
V. Marquina ◽  
M. JimÉnez ◽  
M.L. Marquina ◽  
R. Ridaura ◽  
S. Aburto ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Shape Memory ◽  
Low Temperatures ◽  
Melt Spinning ◽  
Room Temperature ◽  
Mössbauer Spectra ◽  
Magnetic Hysteresis ◽  
Magnetic Behavior ◽  
Temperature Cycle ◽  
Mossbauer Spectra

AbstractMagnetic susceptibility measurements and Mössbauer spectra (MS) were performed on a series of NixFeyAlzB shape memory ribbons obtained by a melt spinning technique. The MS at room temperature show quadrupole splittings of two iron sites. At low temperatures (T<120 K) relaxed magnetic spectra begin to develop and, in one of the samples, a complete resolved magnetic spectrum at 13 K was observed. The overall magnetic susceptibility curves show non Curie-Weiss type behavior with peaks at around 60 K and 35 K. These curves also show magnetic hysteresis in the up-down temperature cycle used during the measurements. We relate our observations with a structural change occurring at temperatures between room temperature and 260 K, a second one around 200 K, and with the developing of spin-glass behavior at low temperatures, when the magnetic influences of Fe and Ni atoms almost compensate each other.

Electronic and magnetic states of Fe ions in the Co2FeBO5

2021 ◽  
Author(s):  
Natalia Kazak ◽  
Yurii V. Knyazev ◽  
Vyacheslav Zhandun ◽  
Juan Bartolomé ◽  
Ana Arauzo ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Room Temperature ◽  
Mössbauer Spectra ◽  
Mossbauer Spectroscopy ◽  
57Fe Mössbauer Spectroscopy ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
57Fe Mossbauer Spectroscopy ◽  
Magnetic States ◽  
Fe Ions

The ludwigite Co2FeBO5 has been studied experimentally using 57Fe Mössbauer spectroscopy and theoretically by means of the DFT+GGA calculations. The room-temperature Mössbauer spectra are composed of four quadrupole doublets corresponding...

Influence of Co-Doping on Magnetic Properties and Magnetocaloric Effect of Fe–Co–Zr–Cu–B Melt-Spun Ribbons

2021 ◽  
Vol 21 (4) ◽  
pp. 2552-2557
Author(s):  
Nguyen Hai Yen ◽  
Nguyen Hoang Ha ◽  
Pham Thi Thanh ◽  
Nguyen Huy Ngoc ◽  
Tran Dang Thanh ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetocaloric Effect ◽  
Melt Spinning ◽  
Room Temperature ◽  
Tangential Velocity ◽  
Magnetic Behavior ◽  
Entropy Change ◽  
Co Doping ◽  
Melt Spun ◽  
Melt Spun Ribbons

In this work, we investigated magnetic properties and magnetocaloric effect in Fe90−xCoxZr7Cu1B2 (x = 0, 1, 2, 3 and 4) melt-spun ribbons. The ribbons were prepared by using a melt-spinning method with a tangential velocity of a copper wheel of 40 m·s-1. The obtained ribbons are almost amorphous. The alloys exhibit typical soft magnetic behavior with low coercivity at room temperature. A minor replacement of Fe by Co gives an increment in Curie temperature (TC) of the alloys to higher temperatures. The TC of the alloys increases from 242 to 342 K with an increase of x from 0 to 4. Maximum magnetic entropy change, ΔSm max, of the alloys, was found to be larger than 0.7 J·kg-1·K-1 in a magnetic field change ΔH of 12 kOe for all the concentrations of Co. High refrigerant capacitys (RC >100 J ·kg-1 with ΔH = 12 kOe) at room temperature region have been obtained for the alloys. The large magnetocaloric effect near room temperature suggests that the alloys can be considered as magnetic refrigerants in the range of 250–350 K.

Structural Characterization of Co70-xNixGa30 Ferromagnetic Shape Memory Alloys

2008 ◽  
Vol 52 ◽  
pp. 103-108 ◽  
Author(s):  
Sidananda Sarma ◽  
A. Srinivasan
Keyword(s):  
Magnetic Susceptibility ◽  
Shape Memory ◽  
Room Temperature ◽  
Structural Parameters ◽  
Ac Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
Ferromagnetic Shape Memory Alloys ◽  
Two Phase ◽  
X Ray ◽  
Ferromagnetic Shape Memory

Polycrystalline ingots of Co70–xNixGa30 (20 ≤ x ≤ 26) ferromagnetic shape memory alloy (FSMA) were prepared by arc melting elemental powders followed by homogenization at 1230 °C for 24 hrs and quenching in liquid nitrogen. Room temperature X-Ray diffraction (XRD) patterns of as-quenched samples exhibited single-phase tetragonal structure for alloy compositions with x = 21 to 26, and a two-phase structure (cubic A2-phase along with weak tetragonal phase) for the alloy with x = 20. Rietveld refinement was performed on the X-ray diffraction patterns to obtain the refined structural parameters. Differential Scanning Calorimeter (DSC) curves recorded from 30 °C to 250 °C revealed martensite-austenite and austenite-martensite transformations in all alloys except the alloy with composition x = 20. Low temperature ac magnetic susceptibility measurements confirmed the existence of martensitic transformations in the alloy with x = 20. The structural transformation temperatures show a linear variation with e/a ratio. All the alloys were ferromagnetic at room temperature. Curie temperature was determined using a high temperature ac magnetic susceptibility measurement set-up.

scholarly journals Investigation of Magnetic Ordering in RCo12B6 (R = Y, Nd) by 57Fe Mössbauer Spectroscopy

1993 ◽  
Vol 46 (5) ◽  
pp. 679 ◽  
Author(s):  
JM Cadogan ◽  
SJ Campbell ◽  
XL Zhao ◽  
E Wu
Keyword(s):  
Basal Plane ◽  
Room Temperature ◽  
Mössbauer Spectra ◽  
57Fe Mössbauer Spectroscopy ◽  
Magnetic Ordering ◽  
Spin Reorientation ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
57Fe Mossbauer Spectroscopy ◽  
Increasing Temperature

Mossbauer spectra of YC012B6 and NdCo12B6 doped with enriched 57Fe have been obtained at various temperatures between 4�2 K and room temperature. The spectrum of YC012B6 at 4�2 K indicates that the Co sublattice orders in the crystallographic basal plane. NdCo12B6 orders along or close to the crystallographic c-axis at 4�2 K and undergoes a spin-reorientation with increasing temperature until at ~55 K the magnetisation lies in or near the basal plane.

scholarly journals Manganese/Yttrium Codoped Strontium Nanohexaferrites: Evaluation of Magnetic Susceptibility and Mossbauer Spectra

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Munirah Almessiere ◽  
Yassine Slimani ◽  
Hakan Güngüneş ◽  
Abdulhadi Baykal ◽  
S.V. Trukhanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Mössbauer Spectra ◽  
Ac Susceptibility ◽  
Sol Gel ◽  
Hyperfine Magnetic Field ◽  
Analytical Techniques ◽  
Magnetic Interactions ◽  
Mossbauer Spectra

Manganese (Mn)- and yttrium (Y)-substituted Sr-nanohexaferrites (MYSNHFs) of composition Sr1−xMnxFe12−xYxO19 (with 0.0 ≤ x ≤ 0.5) were prepared by citrate sol-gel autocombustion method. As-prepared MYSNHFs were characterized via diverse analytical techniques to determine the influence of Mn and Y cosubstitution on their microstructures and magnetic properties. 57Fe Mössbauer spectra of the MYSNHFs were used to evaluate the variation in the line width, isomer shift, quadrupole splitting, and hyperfine magnetic field values. It was shown that the dopant ions could preferentially occupy the 12k, 4f2, and 2b sites. Furthermore, the observed shift in the blocking temperatures of the studied MYSNHFs towards lower values with rising Mn2+ and Y3+ contents was attributed to the overall particles size reduction. Meanwhile, the AC susceptibility of the proposed MYSNHFs revealed that the magnetic interactions were weakened with the increase in dopant contents which was ascribed to the replacement of both Sr2+ and Fe3+ ions by the Mn2+ and Y3+ dopants.

Room temperature Mössbauer spectra of 57Fe-doped La2SrCu2O6, La2CaCu2O6 and La1.6Sr0.4CaCu2O6

1991 ◽  
Vol 181 (1-3) ◽  
pp. 1-10 ◽  
Author(s):  
C. Meyer ◽  
F. Hartmann-Boutron ◽  
Y. Gros ◽  
P. Strobel
Keyword(s):  
Room Temperature ◽  
Mössbauer Spectra ◽  
Mossbauer Spectra

Mössbauer spectra of K3 Fe(CN)6 at low temperatures

1967 ◽  
Vol 24 (7) ◽  
pp. 346-347 ◽  
Author(s):  
W.T Oosterhuis ◽  
G. Lang ◽  
S. Debenedetti
Keyword(s):  
Low Temperatures ◽  
Mössbauer Spectra ◽  
Mossbauer Spectra

Magnetic Behavior of Nanocomposites Prepared in a Vitreous Alumina Gel

1990 ◽  
Vol 206 ◽  
Author(s):  
R. D. Shull ◽  
J. J. Ritter ◽  
A. J. Shapiro ◽  
L. J. Swartzendruber ◽  
L. H. Bennett
Keyword(s):  
Magnetic Susceptibility ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Bulk Material ◽  
Magnetic Behavior ◽  
Subsequent Treatment ◽  
Ferric Nitrate ◽  
Fe Content ◽  
Alumina Gel ◽  
Aqueous Aluminum

ABSTRACTHomogeneous gelled composites of iron and vitreous alumina containing 10-40% Fe have been prepared by room temperature polymerization of aqueous aluminum alkoxide solutions containing ferric nitrate and nitric acid at low pH. Scanning electron microscopy, x-ray diffraction, and Mossbauer spectroscopy demonstrated that this bulk material is comprised of nanometer-sized regions of iron compounds embedded in a vitreous alumina gel matrix. Magnetization data showed that in the as-cured condition these nanocomposites are paramagnetic at room temperature and become either superparamagnetic or ferromagnetic on cooling to 10 K. The magnetic susceptibility increased with the Fe content and with decreasing temperature. Analysis of the temperature dependence of the magnetic susceptibility indicated the magnetic moment per Fe atom was 1.87 µB for the 10% Fe nanocomposite and that it increased linearly with composition to 1.96 µB for the 40% Fe material. Mössbauer effect data showed that subsequent treatment of these materials in a gaseous environment of hydrogen at elevated temperatures (T<400 C) changed the form of the iron in the magnetic regions. These results are compared to that observed for similar nanocomposites prepared using a silica gel matrix.

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