Large Two-Magnon Raman Hysteresis Observed in a Magnetically Uncompensated Hematite Coating across the Morin Transition

A temperature-dependent Raman experiment between 80 and 600 K was performed in a nanoparticulated coating of single-phase hematite grown on a silica substrate. In that range, a thermal Raman shift hysteresis was identified in the vibrational modes that accompanies the Morin transition, observing lar...

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Bibliographic Details
Published in:Coatings (Basel) 2022-04, Vol.12 (4), p.540
Main Authors: López-Sánchez, Jesús, del Campo, Adolfo, Román-Sánchez, Sara, Rodríguez de la Fuente, Óscar, Carmona, Noemí, Serrano, Aída
Format: Article
Language:English
Subjects:
Antiferromagnetism
Coating
Coercivity
Cooling
Ferromagnetism
Glass substrates
Hematite
Hysteresis
Magnetic fields
Magnons
Morphology
Substrates
Temperature
Temperature dependence
Vibration mode
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Summary:A temperature-dependent Raman experiment between 80 and 600 K was performed in a nanoparticulated coating of single-phase hematite grown on a silica substrate. In that range, a thermal Raman shift hysteresis was identified in the vibrational modes that accompanies the Morin transition, observing large effects in the two-magnon Raman frequency position and in its relative intensity. Interestingly, no decrease in coercivity occurs when the hematite crosses the Morin transition below 230 K. The spin-flop processes produced in the coating leads to a strong decompensation of the surface spins, generating a ferromagnetic component over the whole temperature range studied. Such unusual effects might be promoted by a certain degree of structural disorder and the stresses produced by the nanoparticulation growth approach of the hematite coating. As a result, a high stability of the two-magnon excitation is obtained over a wide temperature range and considerable advances are made for the development of spintronic devices based on semiconductor antiferromagnetic materials.
ISSN:2079-6412
2079-6412
DOI:10.3390/coatings12040540