Magnetotransport properties of nanogranular composites with low-field positive magnetoresistance
| Autor: | M. M. Kulyk, Sergey M. Ryabchenko, A.V. Bodnaruk |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Magnetic moment Magnetoresistance Field (physics) Film plane General Physics and Astronomy Conductivity 01 natural sciences Magnetic field Condensed Matter::Materials Science Magnetization 0103 physical sciences 010306 general physics Anisotropy |
| Zdroj: | Low Temperature Physics. 46:792-797 |
| ISSN: | 1090-6517 1063-777X |
| DOI: | 10.1063/10.0001542 |
| Popis: | A low-temperature feature is detected in nanogranular magnetic films with perpendicular anisotropy that have a low-field positive magnetoresistance: positive magnetoresistance is observed during the initial magnetization of the demagnetized sample, but is absent when the magnetic field is removed and/or during subsequent magnetizations. This effect is studied using a Cox(Al2On)1−x film with x = 0.60, consisting of Co metal nanogranules in an Al2On insulating matrix with n close to 3. It is found that together with perpendicular anisotropy, the film has local in-plane anisotropy with randomly oriented easy axes, which prevents the reorientation of the granules’ magnetic moment projections in the film plane below a certain blocking temperature. The restoration of the local short-range order in the orientation of the magnetic moments of the demagnetized film’s neighboring granules, which is optimal for conductivity and is destroyed by the introduction of a magnetic field, is prevented at temperatures below the blocking temperature and is not restored during subsequent cycles of introducing/removing the magnetic field without heating to temperatures above the blocking temperature. |
| Databáze: | OpenAIRE |
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