TY - JOUR
T1 - Distribution of niobium in an Fe-Pt-Nb magnet
AU - Tanaka, Y.
AU - Udoh, K.
AU - Hisatsune, K.
AU - Sakurai, T.
N1 - Funding Information:
The authors wish to acknowledge the help of Mr N. Kimura who provided magnet samples and measured magnetic properties. We are grateful to Dr K. Hono who provided many helpful suggestions. A part of this work was carried out under the Visiting Researcher’s Program 95-124 and 96-119 of the Institute for Materials Research, Tohoku University. This research was partly supported by Grant-in-Aid for Encouragement of Young Scientists 08771802 from the Ministry of Education, Science, Sports and Culture, Japan.
PY - 1998/7/15
Y1 - 1998/7/15
N2 - The role of Nb addition to improve the hard magnetic properties in FePt magnet was investigated by characterizing microstructures of both Fe-39.5 at.%Pt binary and Fe-39.5 at.%Pt-0.75 at.%Nb ternary alloys using transmission electron microscopy and atom probe field ion microscopy. In the as-quenched ternary alloy, the FePt ordered domains with a tweed contrast were observed as well as in the binary alloy. However, the ordered domain size of the ternary alloy was slightly smaller than that of the binary alloy and comparable to the thickness of magnetic domain wall. Although the coercivity of the as-quenched ternary alloy was small, subsequent annealing produced high coercivity. Nb was rarely solved in the FePt ordered phase and was concentrated in spherical particles of sub-microns in size. These particles may work as a pinning site against magnetic domain wall motion. Another possibility is that the change in composition ratio between Fe and Pt may be responsible to the magnetic property change.
AB - The role of Nb addition to improve the hard magnetic properties in FePt magnet was investigated by characterizing microstructures of both Fe-39.5 at.%Pt binary and Fe-39.5 at.%Pt-0.75 at.%Nb ternary alloys using transmission electron microscopy and atom probe field ion microscopy. In the as-quenched ternary alloy, the FePt ordered domains with a tweed contrast were observed as well as in the binary alloy. However, the ordered domain size of the ternary alloy was slightly smaller than that of the binary alloy and comparable to the thickness of magnetic domain wall. Although the coercivity of the as-quenched ternary alloy was small, subsequent annealing produced high coercivity. Nb was rarely solved in the FePt ordered phase and was concentrated in spherical particles of sub-microns in size. These particles may work as a pinning site against magnetic domain wall motion. Another possibility is that the change in composition ratio between Fe and Pt may be responsible to the magnetic property change.
KW - Atom probe field ion microscopy
KW - Hard magnet
KW - L1 structure
KW - Order-disorder phase transition
KW - Transmission electron microscopy
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U2 - 10.1016/S0921-5093(98)00554-1
DO - 10.1016/S0921-5093(98)00554-1
M3 - Article
AN - SCOPUS:0013369704
VL - 250
SP - 164
EP - 168
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
IS - 1
ER -