Effect of Ga and Zr Substitution on the Properties of Dy2Fe17−XZrX and Dy2Fe16Ga1−xZrx (0 ≤ x ≤ 1) Intermetallic Compounds Prepared via Arc Melting Process

The effects of substitution of Zr and Ga on the structural and magnetic properties of Dy2Fe17 intermetallic compound were investigated in this study. The Rietveld analysis confirmed that the crystalline system was a Th2Ni17 structure. Lattice parameters a (Å) and c (Å), unit cell volume (Å3), and bonding distance (Å) were calculated using Rietveld analysis. The unit cell volume of Dy2Fe17−xZrx and Dy2Fe16Ga1−xZrx increased linearly with Zr and Ga substitution. The Curie temperature (Tc) of Dy2Fe17−xZrx and Dy2Fe16Ga1−xZrx was found to be Zr content-dependent. The maximum Curie temperatures were observed at 510 K (x = 0.75 Zr content) for Dy2Fe17−xZrx and 505.1 K (x = 0.5 Zr content) for Dy2Fe16Ga1−xZrx, which are 102 K and 97 K higher than the value found for Dy2Fe17, respectively. The room-temperature Mössbauer analysis showed a decrease in the average hyperfine field and increases in the isomer shift with Zr doping. The overall improvement in Curie temperature with the substitution strategy of Zr–Ga substitution in 2:17 intermetallic compounds could find potential use of these magnetic compounds in high-temperature applications.

Structural, Magnetic and Mössbauer Studies of Ga and Zr Doped Dy2Fe17-XZrX and Dy2Fe16Ga1-xZrx (x=0.00, 0.25, 0.50, 0.75, 1.00)

In this article, the effect of substitution of Zr and Ga in Dy2Fe17 prepared by arc melting technique are studied. The substitution of Zr and Ga in Dy2Fe17 was found to have an important effect on their structure and magnetic properties. The Rietveld analysis conformed that the crystalline system wereTh2Ni17 structure. Lattice parameters a (Å) and c (Å), unit cell volume (Å3), bonding distance (Å) were calculated by using Rietveld analysis. The unit cell volume of Dy2Fe17-xZrx and Dy2Fe16Ga1-xZrx increase linearly with the Zr and Ga substitution. The substitution of Zr and Ga are limited up to x=1 in order to avoid the decrease in saturation magnetization. The Curie temperature (Tc) of Dy2Fe17-xZrx and Dy2Fe16Ga1-xZrx are found to be Zr content dependent. The Curie temperature is found to be increasing first and then decrease for higher Zr content. The maximum curie temperature was observed 510K at x = 0.75 for Dy2Fe17-xZrx and 505.1 K at x = 0.5 for Dy2Fe17-xZrx which are102 K and 97 K higher than Dy2Fe17. The room temperature Mössbauer analysis shows the decrease in average hyperfine field and increase in isomer shift with Zr doping.

Effects of Co, Ni, and Cr addition on microstructure and magnetic properties of amorphous and nanocrystalline Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6) alloys

Mössbauer spectra and thermomagnetic curves for the Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6) alloys in the as-quenched state and after the accumulative annealing in the temperature range 600–800 K for 10 min are investigated. The parent Fe86Zr7Nb2Cu1B4 amorphous alloy is paramagnetic at room temperature, and substitution of 6 at.% of Fe by Co, Ni, and CoCr changes the magnetic structure – the alloys become ferromagnetic, whereas replacing 6 at.% of Fe with Cr preserves the paramagnetic state. After the heat treatment at 600 K, the decrease of the average hyperfine field induction, as compared to the as-quenched state, is observed due to the invar effect. After this annealing, the Curie temperature for all investigated alloys decreases. The accumulative annealing up to 800 K leads to the partial crystallization; α-Fe or α-FeCo grains with diameters in the range of 12–30 nm in the residual amorphous matrix appear.

The hyperfine field at Ti nuclei in Fe and Ni and the g factor of the 160-keV 7/2− level of 47Ti

Integral rotation of the 3/2+ 320-keV level of 45Ti and the 7/2− 160 keV level of 47Ti recoil implanted in iron and nickel were measured following (α,n) reactions in 42Ca and 44Ca on magnetized backings. The average hyperfine field at 45Ti nuclei is Hhf(TiFe) = −45 ± 10 kOe and Hhf(TiNi) = −15 ± 3kOe. The g factor of the 7/2− first excited state of 47Ti is −0.55 ± 0.17.

Implantation perturbed angular correlation experiments in iron after inelastic proton scattering

Hyperfine interactions in iron metal have been studied by the standard IMPACT technique, populating the 0.847 MeV, 10.4 ps state of 56 Fe and the 1.408 MeV, 1.42 ps state of 54 Fe via the ( p, p' ) nuclear reaction. Several experiments on 56 Fe were performed independently at the University of Wisconsin Tandem Van de Graaff accelerator laboratory and at the Rutgers-Bell facility. In all cases, the experiments yielded shifts of less than 0.005 rad in the correlation pattern. The low results imply that the average hyperfine field in iron implanted into iron is less than 175 kG during the first 10 ps after implantation. The results are discussed in terms of possible radiation damage and transient field effects, and microscopic details of the IMPACT process are considered.