Flash annealing and magnetic interactions in Pr{sub 4}Fe{sub 78}B{sub 18}

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.364793· OSTI ID:496482

Villas-Boas, V; Romero, S A; Missell, F P ^[1]

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1. Instituto de Fisica, Universidade de Sao Paulo, C P 66318, 05315-970 Sao Paulo, S P (Brazil)

Enhanced-remanence Pr{sub 4}Fe{sub 78}B{sub 18} alloys were produced by using a high heating rate/short time anneal, known as flash annealing. Partially amorphous ribbons were produced by melt spinning and then annealed for 10{endash}20 s at temperatures 600{endash}820{degree}C by passing current through the sample. Coercivity increases of up to 15{percent} were systematically observed in relation to furnace-annealed material. M{umlt o}ssbauer spectra showed that flash annealing resulted in significant amounts of Pr{sub 2}Fe{sub 23}B{sub 3} and reduced quantities of {alpha}-Fe. Our best flash-annealed material (600 {degree}C/20 s) had H{sub c}=3.5kOe, M{sub r}/M{sub s}=0.77, and (BH){sub max}=11.1MGOe. The magnetic remanence curves M{sub r}(H), obtained for different initial demagnetized states (thermal, ac, dc{sup +}, dc{sup {minus}}), and the remanence M{sub d}(H), obtained for an initially saturated state, were determined for the construction of Henkel plots (HP). The HP for ac and thermally demagnetized Pr{sub 4}Fe{sub 78}B{sub 18} are very similar and show both magnetizing and demagnetizing interactions. There is no significant difference between the HP of furnace and flash-annealed samples. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 496482
• Report Number(s): CONF-961141--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BORON ALLOYS
COERCIVE FORCE
DEMAGNETIZATION
EXCHANGE INTERACTIONS
FERROMAGNETIC MATERIALS
IRON ALLOYS
MAGNETIC PROPERTIES
MICROSTRUCTURE
PRASEODYMIUM ALLOYS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION