Evidence for weak ferromagnetic moment within the basal plane of hematite natural crystals at low temperature

Lowerature magnetization of hematite within the basal plane has been studied in a collection of natural crystals by means of torque magnetometry. Comparison between the torque curves at room temperature and at 77 K allows identification of a weak ferromagnetic moment constrained within the basal pla...

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Detalles Bibliográficos
Autores: Martín Hernández, Fátima, Hirt, A. M.
Tipo de recurso: artículo
Fecha de publicación:2013
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/92981
Acceso en línea:http://hdl.handle.net/10261/92981
Access Level:acceso abierto
Palabra clave:Hematite
Low-temperature properties
Ferromagnetic moment
Anisotropy
Magnetic transition
Torque magnetometry
Descripción
Sumario:Lowerature magnetization of hematite within the basal plane has been studied in a collection of natural crystals by means of torque magnetometry. Comparison between the torque curves at room temperature and at 77 K allows identification of a weak ferromagnetic moment constrained within the basal plane at temperatures well below the Morin transition. Annealing the samples produces the expected reduction of the weak ferromagnetic moment, but there is also a relationship between the ferromagnetic moment before and after annealing. Lowerature measurements after the annealing experiment reveal the presence of a weak ferromagnetic moment that survives the annealing. This observation suggests the magnetic structure of natural hematite crystals below the Morin transition can still be a carrier of magnetization. Key Points A weak ferromagnetic (WFM) moment is detected below the Morin transition The WFM lies within the basal plane Natural Hematite is not a pure AF below TM ©2013. American Geophysical Union. All Rights Reserved.