"NdMn6-xFexGe6 , SmMn6-xFexGe6 , NdMn6-xFexSn6 , and SmMn6-xFexSn6 have been studied by x-ray and neutron diffraction techniques and bulk magnetization measurements. NdMn6-xFe6Sn6 has also been studied by Mӧssbauer spectroscopy. All germanides crystallize in the disordered YCo6Ge6-type structure, whereas the stannides crystallize in the HoFe6Sn6-type and the TbFe6Sn6-type structure for the non-substituted samples and the iron-containing samples, respectively. Iron randomly replaces manganese on all sites in both germanides and stannides. The a, b, and c lattice parameters decrease with increasing iron content for all samples. The net magnetization decreases with increasing iron content for all germanides and the stannides with iron content larger than x = 1.24, whereas the net magnetization increases with increasing iron content for the stannides with iron content less than x = 1.24. The magnetic moment of the iron sublattice couples antiferromagnetically with the ferromagnetically coupled manganese and rare-earth moments for the germanides, whereas there is ferromagnetic coupling between the iron sublattice and the ferromagnetically coupled manganese and rare-earth sublattices for the stannides. Spin reorientation occurs in all neodymium- containing samples in which the easy magnetization direction cants away from the c-axis and the a-axis with increasing temperature for the germanides and the stannides, respectively. The easy magnetization direction of all samarium-containing samples is parallel to, or at least aligned at a small angle with, the basal plane of the unit cell at room temperature. An analysis of the Mn-Mn interatomic distances in RMn6X6 and RMn6-xFexX6, where R is a rare earth and X is germanium or tin, indicates that there is a critical Mn-Mn distance, dT ≈ 2.6145 Å, below and above which the coupling within the manganese sublattice is anti ferromagnetic and ferromagnetic, respectively"--Abstract, page iv.
James, William Joseph
Long, Gary J., 1941-
Pringle, Oran Allan
Switzer, Jay A., 1950-
Yelon, William B.
Grandjean, Fernande, 1947-
Ph. D. in Chemistry
University of Missouri--Rolla
Journal article titles appearing in thesis/dissertation
- The atomic and magnetic structures of NdMn6-xFexGe6
- Magnetic and crystallographic properties of SmMn6-xFexGe6
- Magnetic and crystallographic properties of NdMn6-xFexSn6
- The atomic and magnetic structures of SmMn6-xFexSn6
- An analysis of manganese-manganese distance in RMn6X6, where R is a rare earth and X is germanium or tin
xiv, 143 pages
© 2000 Jun Han, All rights reserved.
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu/record=b4514965~S5
Han, Jun, "The atomic and magnetic structures of several iron-substituted rare-earth manganese germanides and stannides" (2000). Doctoral Dissertations. 1364.
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