Magnetic analysis of Pr80Fe15(B1-xCx)(5) alloys (0.85 <= x <= 1.00)

A magnetic study of Pr80Fe15(B1-xCx)(5) alloys with low B-content (0.85 les s than or equal to x less than or equal to 1.00) in the as-cast state and a nnealed at 600 degreesC has been performed. In as-cast samples, a metastabl e eutectic phase A(1) is present in all samples. For x = 1.00 in as-cast st ate, coarse and quite corrosive carbides are also present. With thermal tre atment at 600 degreesC for 2 h, these phases disappear and a hard needle-li ke magnetic phase, known as D-1, with T-C = 224 degreesC and H-I(C) = 2.4 k Oe at room temperature, is the only phase observed. The coercivity of the a nnealed Pr80Fe15C5 alloy strongly increases with decreasing temperature (H- I(C) = 44.6 kOe at 4.2 K), confirming the high magnetocrystalline anisotrop y of D-1. A comparison of the chi (AC)(T) curves for Pr80Fe15X5, X = B, C, indicates that D-1 is different from the ternary carbide RE2Fe14C. (C) 2001 Elsevier Science B.V. All rights reserved.