Structural and magnetic properties of Nd{sub 2}Fe{sub 17-{delta}}Ga{sub {delta}} ({delta}{<=}2)
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Laboratoire des Champs Magnetiques Intenses, CNRS/MPI, 38042 Grenoble, (France)
- Neutron Program for Materials Research, Steacie Institute for Molecular Sciences, NRC, Chalk River, Ontario K0J 1P0, (Canada)
- Department of Physics, Centre for the Physics of Materials, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8, (Canada)
- Department of Material Science and Mineral Engineering, University of California, Berkeley, California 94720 and Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Magnetization measurements of Nd{sub 2}Fe{sub 17-{delta}}Ga{sub {delta}} ({delta}=0-2) show that the saturation magnetization, M{sub s}, decreases with an increase in Ga content from 40.4 {mu}{sub B}/f.u. for Nd{sub 2}Fe{sub 17} to 36.1 {mu}{sub B}/f.u. for Nd{sub 2}Fe{sub 15}Ga{sub 2} at 4.2 K. Neutron diffraction data at 25 K show that the magnetic moment of Fe depends on its crystallographic site and decreases in the order Fe(6c)>Fe(18f){>=}Fe(18h){>=}Fe(9d). The magnetic moments of Fe(9d), Fe(18f), and Fe(18h) are found to be practically independent of the Ga content. However, the magnetic moment of Fe(6c) decreases from 2.81(9) {mu}{sub B} in Nd{sub 2}Fe{sub 17} to 2.14(9) {mu}{sub B} in Nd{sub 2}Fe{sub 15}Ga{sub 2}. The decrease of the Fe(6c) moment clearly reduces the exchange interaction between Fe(6c)-Fe(6c) dumbbell pairs which explains the decrease in the anomalous thermal expansion with an increase in Ga concentration. The reduced Fe(6c)-Fe(6c) exchange interaction may also play an important role in increasing the Curie temperature, T{sub C}, with Ga content; T{sub C} increases from 327 K in Nd{sub 2}Fe{sub 17} to 535 K in Nd{sub 2}Fe{sub 15}Ga{sub 2}. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20216232
- Journal Information:
- Journal of Applied Physics, Vol. 87, Issue 9; Other Information: PBD: 1 May 2000; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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