G. A. Pérez Alcázar

Mössbauer effect study of magnetic properties of Fe1−qAlq, 0<q≤0.5, alloys in the disordered phase

The authors report the experimental study by Mossbauer spectroscopy, at room temperature (RT), of Fe-Al alloys in the disordered phase, with an Al concentration q in the range 0<q<or=0.5. The alloys are all ferromagnetic and from the fitting of the Mossbauer spectra with hyperfine field (HF) distribution, they obtained the dependence of the average HF with q. It decreases gradually with increasing q and reaches zero at a critical concentration of 47.5 at.% Al. The HF distributions show peaks equally spaced Delta H=24 kOe apart. This value corresponds to the reduction in the average magnetic field due to the substitution of one nearest-neighbour Fe by an Al atom. The magnetic ordering temperatures were obtained and compared with theoretical results.

Mössbauer and x-ray study of mechanically alloyed Fe–Ni alloys around the Invar composition

Fe100−xNix powders (22.5≤x≤40 at.%) mechanically alloyed (MA) for 10 h were characterized by x-ray diffraction (XRD) and transmission 57Fe Mossbauer spectrometry (TMS). In all of this composition range, the nanostructured alloys consist of two crystalline phases, body-centred cubic (BCC) and face-centred cubic (FCC). The Mossbauer spectra were fitted by means of a new fitting model involving two hyperfine magnetic field distributions (HMFDs), and a narrow singlet. One HMFD corresponds to the ferromagnetic BCC grains (tetrataenite), and the other to the ferromagnetic FCC grains (taenite), and the narrow singlet to paramagnetic FCC grains (antitaenite or superparamagnetic FCC grains). The Ni content dependence of the hyperfine field at 57Fe nuclei of the FCC phase gives evidence for some jump at about 32.5 at.% Ni, attributed to Invar anomaly.

Magnetic properties of Fe−Mn−Al alloy system in the FCC disordered phase

AbstractIn this work we report the experimental studies of Fe−Mn−Al alloys in the FCC disordered phase at room temperature by Mössbauer spectroscopy and X-ray diffraction. In this phase the alloys are antiferromagnetic with a constant mean hyperfine field ( % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFH0dXde9LqFHe9Lq% pepeea0xd9q8as0-LqLs-Jirpepeea0-as0Fb9pgea0lrP0xe9Fve9% Fve9qapdbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmisayaara% aaaa!3A21!

Magnetic phase diagram of the FexMn0.6−xAl0.40 alloys series

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Magnetic properties of FexMn0.3Al0.7-x (0.275 ⩽ x ⩽ 0.525) disordered alloys

) near 26 kOe in the composition range from 0 to 7.5 at.% Al and 50 to 65 at.% Fe. When the Al or Fe concentration increases, the % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFH0dXde9LqFHe9Lq% pepeea0xd9q8as0-LqLs-Jirpepeea0-as0Fb9pgea0lrP0xe9Fve9% Fve9qapdbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmisayaara% aaaa!3A21!

Mössbauer evidence of reentrant spin-glass phase in the Fe0.45Mn0.25Al0.30 disordered alloy

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