TY - JOUR
T1 - Nanocluster-containing mesoporous magnetoceramics from hyperbranched organometallic polymer precursors
AU - Sun, Q.
AU - Lam, J. W.Y.
AU - Xu, K.
AU - Xu, H.
AU - Cha, J. A.K.
AU - Wong, P. C.L.
AU - Wen, G.
AU - Zhang, X.
AU - Jing, X.
AU - Wang, F.
AU - Zhong Tang, B.
PY - 2000
Y1 - 2000
N2 - Pyrolysis of hyperbranched poly[1,1'-ferrocenylene(methyl)silyne] (5) yields mesoporous, conductive, and magnetic ceramics (6). Sintering at high temperatures (1000-1200 °C) under nitrogen and argon converts 5 to 6N and 6A, respectively, in ~48-62% yields. The ceramization yields of 5 are higher than that (~36%) of its linear counterpart poly[1,1'-ferrocenylene(dimethyl)silylene] (1), revealing that the hyperbranched polymer is superior to the linear one as a ceramic precursor. The ceramic products 6 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture constructed of tortuously interconnected nanoclusters. The iron contents of 6 estimated by EDX are 36-43%, much higher than that (11%) of the ceramic 2 prepared from the linear precursor 1. The nanocrystals in 6N are mainly α-Fe2O3 whereas those in 6A are mainly Fe3Si. When magnetized by an external field at room temperature, 6A exhibits a high-saturation magnetization (M(s) ~ 49 emu/g) and near-zero remanence and coercivity; that is, 6A is an excellent soft ferromagnetic material with an extremely low hysteresis loss.
AB - Pyrolysis of hyperbranched poly[1,1'-ferrocenylene(methyl)silyne] (5) yields mesoporous, conductive, and magnetic ceramics (6). Sintering at high temperatures (1000-1200 °C) under nitrogen and argon converts 5 to 6N and 6A, respectively, in ~48-62% yields. The ceramization yields of 5 are higher than that (~36%) of its linear counterpart poly[1,1'-ferrocenylene(dimethyl)silylene] (1), revealing that the hyperbranched polymer is superior to the linear one as a ceramic precursor. The ceramic products 6 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture constructed of tortuously interconnected nanoclusters. The iron contents of 6 estimated by EDX are 36-43%, much higher than that (11%) of the ceramic 2 prepared from the linear precursor 1. The nanocrystals in 6N are mainly α-Fe2O3 whereas those in 6A are mainly Fe3Si. When magnetized by an external field at room temperature, 6A exhibits a high-saturation magnetization (M(s) ~ 49 emu/g) and near-zero remanence and coercivity; that is, 6A is an excellent soft ferromagnetic material with an extremely low hysteresis loss.
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U2 - 10.1021/cm000094b
DO - 10.1021/cm000094b
M3 - Article
AN - SCOPUS:0033810323
SN - 0897-4756
VL - 12
SP - 2617
EP - 2624
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 9
ER -