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Full-Text Articles in Condensed Matter Physics
Anisotropy Of Exchange Stiffness And Its Effect On The Properties Of Magnets, K. D. Belashchenko
Anisotropy Of Exchange Stiffness And Its Effect On The Properties Of Magnets, K. D. Belashchenko
Kirill Belashchenko Publications
Using the spin-spiral formulation of the tight-binding linear muffin-tin orbital method, the principal components of the exchange stiffness tensor are calculated for typical hard magnets including tetragonal CoPt-type and hexagonal YCo5 alloys. The exchange stiffness is strongly anisotropic in all studied alloys. This anisotropy makes the domain wall surface tension anisotropic. Competition between this anisotropic surface tension and magnetostatic energy controls the formation and dynamics of nanoscale domain structures in hard magnets. Anisotropic domain wall bending is described in detail from the general point of view and with application to cellular Sm–Co magnets. It is shown that the repulsive …
Tem Study Of Crystalline Structures Of Cr–N Thin Films, Xingzhong Li, J. Zhang, David J. Sellmyer
Tem Study Of Crystalline Structures Of Cr–N Thin Films, Xingzhong Li, J. Zhang, David J. Sellmyer
Nebraska Center for Materials and Nanoscience: Faculty Publications
Cr–N films were grown on Si (001) substrates by reactive magnetron sputtering under an N2/Ar atmosphere at room temperature. The composition of the films, expressed as Cr1–xNx, can be varied by changing the N2/Ar pressure ratio during the synthesis process. Crystalline states of Cr–N films have been studied using electron diffraction. It is well known that two intermediate phases, Cr2N (hexagonal) and CrN (cubic), exist in the Cr–N system, and small variations around the ideal stoichiometry are tolerated. The present study shows that cubic CrN with vacancies rather than hexagonal Cr2 …
Spin Uncoupling In Free Nb Clusters: Support For Nascent Superconductivity, Ramiro Moro, Shuangye Yin, Xiaoshan Xu, Walt A. De Heer
Spin Uncoupling In Free Nb Clusters: Support For Nascent Superconductivity, Ramiro Moro, Shuangye Yin, Xiaoshan Xu, Walt A. De Heer
Xiaoshan Xu Papers
Molecular beam Stern-Gerlach deflection measurements on Nb clusters (NbN, N <100) show that at very low temperatures the odd-N clusters deflect due to a single unpaired spin that is uncoupled from the cluster. At higher temperatures the spin is coupled and no deflections are observed. Spin uncoupling occurs concurrently with the transition to the recently found ferroelectric state, which has superconductor characteristics [Science 300, 1265 (2003)]. Spin uncoupling (also seen in V, Ta, and Al clusters) is analogous to the reduction of spin-relaxation rates observed in bulk superconductors below Tc.