التفاصيل البيبلوغرافية
| العنوان: |
High temperature magnetic studies on Bi1-xCaxFe1−yTiyO3-δ nanoparticles: Observation of Hopkinson-like effect above TN. |
| المؤلفون: |
Mocherla, Pavana S. V., Prabhu, D., Sahana, M. B., Hebalkar, Neha Y., Gopalan, R., Ramachandra Rao, M. S., Sudakar, C. |
| المصدر: |
Journal of Applied Physics; 2018, Vol. 124 Issue 7, pN.PAG-N.PAG, 11p, 1 Diagram, 9 Graphs |
| مصطلحات موضوعية: |
NANOPARTICLES, TEMPERATURE, OCTAHEDRAL molecules, X-ray diffraction, ELECTRON microscopy |
| مستخلص: |
The magnetic properties of Bi1-xCaxFe1-yTiyO3-δ (BCFO: y = 0 and BCFTO: x = y) nanoparticles are studied across a wide range of temperatures (20 K to 960 K) for different Ca (and Ti) concentrations [x (= y) = 0, 0.025, 0.05, and 0.1]. X-ray diffraction and electron microscopy revealed the gradual emergence of the orthorhombic phase (Pnma) with an increase in the Ca2+ content in BCFO, contrary to the retention of parent rhombohedral symmetry (R3c) in Ca2+-Ti4+ co-doped BCFTO. XPS indicates the presence of 3+ valence states for Bi and Fe and under-coordinated defect peaks in O 1s spectra. The ordering of oxygen vacancies in BCFO affects the FeO6 octahedral alignment, resulting in a systematic shift of Fe-O Raman modes. Oxygen vacancies formed due to Ca2+ doping in BCFO and the non-magnetic Ti4+ ion at the Fe3+ site in BCFTO disrupt the spin-cycloid propagation in BiFeO3, largely influencing the magnetic properties. These substitutional changes, in addition to the large surface area, are the sources of net magnetization in these systems. Magnetic hysteresis and field dependent zero field cooled-field cooled curves indicate the combined presence of anti-ferromagnetic and ferromagnetic components in BCFO and BCFTO nanoparticles. High temperature magnetic studies present a clear bifurcation of magnetic Néel transition centered at ∼600 K associated with the structural variation in BCFO. A strong anomaly observed at 860 ± 40 K in all the samples suggests a Hopkinson-like effect arising due to sudden loss of anisotropy by the FM component. [ABSTRACT FROM AUTHOR] |
|
Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| قاعدة البيانات: |
Complementary Index |
Find this article in full text from Scitation.