W. K. Warburton

Bio: W. K. Warburton is an academic researcher. The author has contributed to research in topics: Crystal structure & Rietveld refinement. The author has an hindex of 1, co-authored 1 publications receiving 11 citations.

Combined neutron and x-ray powder diffraction study of Fe 0.50 Co 0.48 V 0.02

Abstract: The large number of constituent elements and high symmetry of the ordered Fe-Co-V alloys make a complete solution of its structure impossible from a single diffraction experiment. We have carried out a Rietveld refinement of the site occupancies for a partially ordered Fe-Co-V alloy using both neutron and anomalous dispersion x-ray powder diffraction data in order to obtain a complete crystallographic solution to its structure. Contrary to previous assumptions that V occupies both sites randomly or magnetic and Moessbauer studies that suggest that V has a site preference for the Fe sublattice, we find that the V dopant preferentially occupies the Co sites.

Soft magnetic FeCo alloys: alloy development, processing, and properties

Abstract: FeCo intermetallic alloys are well known to possess a unique combination of high saturation magnetisation, high Curie temperature, low magnetocrystalline anisotropy and good strength. They are ideally suited for applications requiring high flux densities. Intense research and development efforts over the years resulted in significant improvements in mechanical properties and better understanding of phase transformations in FeCo alloys. However, the high cost of the alloys has prevented their widespread applications. Emerging needs for soft magnetic materials to operate at high temperatures have caused renewed interest in FeCo alloys. The earlier studies are summarised in this review with special emphasis on phase transformations, processing, mechanical, magnetic and electrical properties of binary, ternary and more complex FeCo alloys. Current interest in developing nanocrystalline and thin films based on FeCo compositions is also summarised. The research areas that need to be addressed are also emphasised to clearly elucidate the effects of alloying additions and processing on the electrical and magnetic properties and on the high temperature mechanical properties of these alloys.

Probing the Relationship of Long-Range Order in Nanodomain FeCo Alloys with Ternary Additions Using Neutron Diffraction

Abstract: The effects of tailoring FeCo alloys with addition of ternary elements Pt, Pd, Mn, Ir, and Re have been investigated. In the composition range of 30 to 70 pct Co, FeCo alloys undergo a continuous order-disorder phase transition at a maximum temperature of 730 °C at the equiatomic composition. The effects of temperature and composition on the degree of long-range order in six alloys (Fe70Co30, Fe67Co30Pt3, Fe67Co30Pd3, Fe67Co30Mn3, Fe67Co30Ir3, and Fe67Co30Re3; at. pct) were compared using neutron diffraction. The transition goes along with growing of antiphase domains during the heating process.

Influences of rapid annealing and substrate temperature on the magnetic properties of Co-Fe-V films

Abstract: In this paper we report the results of a systematic investigation of influences of the deposition conditions on the microstructure and magnetic properties of Co-Fe-V thin films. The magnetic softness was optimized when the thin films were deposited at a sputtering pressure of 2mTorr and a sputtering power density of 3.82W∕cm2. A strong modification in the coercivity and its shape with respect to film thickness and substrate temperature was observed. Nanocrystalline Co49.12Fe48.65V2.23 thin films exhibited the superior soft magnetic properties (Bs=25.7kG, Hc=1.2Oe, Hk=24.5Oe) and the high electrical resistivity of 300μΩcm, which are beneficial for high-frequency and temperature applications. It was also found that rapid annealing caused considerable changes in the microstructure and hence the magnetic properties of the Co-Fe-V thin films.