| Autor: |
A.M. Keen, H. S. Derbyshire, S.N. Mozley, C. Norris, Colin W. Binns, S.H. Baker |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Solid State Communications. 107:523-526 |
| ISSN: |
0038-1098 |
| Popis: |
Magnetic ordering in bulk Mn and nanoscale Mn islands deposited on highly oriented pyrolytic graphite has been investigated with spin-polarised photoelectron diffraction (SPPED). Results for the bulk film show the expected step in the ratio of intensities of the Mn 3 s core level 5 S and 7 S multiplets. This occurs at a temperature of 505 ± 20 K or 5.3 times T N , the bulk Neel temperature and compares well with similar data from Mn compounds. In contrast the equivalent step observed with mesoscopic Mn islands of mean size 6 nm is found to occur at 85 ± 15 K, that is, at about T N . The high proportion of surface atoms (∼25%) in the nanoscale system produced an enhanced photoemission signal from the surface allowing a deconvolution of surface and interior contributions to the 3 s spectra. We thus show that the step in the ratio of multiplet intensities arises entirely from the surface component of the 3 s spectrum. This supports a recent interpretation that the step is due to a surface specific transition in longrange magnetic order that can be well above T N ,bulk for antiferromagnets and T C ,bulk for ferromagnets. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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