Quantum size effects on magnetism in Eu2MnHfO6 nanoparticles: Role of surface-to-volume ratio, magnetic blocking, and magnetic phase transitions
In this paper, we investigate the quantum size effects on Eu2MnHfO6 (EMHO) nanoparticles (NPs) synthesized via sol–gel and annealed at 500, 800, and 1000 °C. XRD confirmed a cubic Fd3̅m structure across all samples, with NP sizes increasing from 7.4 nm to 23.8 nm. Smaller NPs displayed features of...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-08-01
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| Series: | Results in Physics |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211379725002207 |
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| Summary: | In this paper, we investigate the quantum size effects on Eu2MnHfO6 (EMHO) nanoparticles (NPs) synthesized via sol–gel and annealed at 500, 800, and 1000 °C. XRD confirmed a cubic Fd3̅m structure across all samples, with NP sizes increasing from 7.4 nm to 23.8 nm. Smaller NPs displayed features of quantum dots (QD) and weakened Mn/Hf–O–Mn/Hf bonding due to broken surface coordination, as seen in FTIR spectra. Magnetic measurements revealed size-dependent behaviour: smaller NPs exhibited surface-driven phenomena like blocking temperature (TB) and surface spin effects (TSE), while larger NPs (23.8 nm) showed bulk-like super-exchange interactions with distinct Néel (TN) and Curie (TC) temperatures. Local magnetic inhomogeneities indicating a Griffiths phase (GP) were found in the smallest and largest particles, overlapping with TC. These novel results underscore how surface-to-volume ratios influence magnetic transitions, supporting a modified Curie–Weiss law that distinguishes surface and volume effects with coordination variations in MNPs. |
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| ISSN: | 2211-3797 |