Magnetic behaviour of interacting antiferromagnetic nanoparticles

• Published in: Journal of physics. Condensed matter Vol. 24; no. 26; p. 266001
• Main Authors: Markovich, V, Puzniak, R, Skourski, Y, Wisniewski, A, Mogilyanski, D, Jung, G, Gorodetsky, G
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 04.07.2012; Institute of Physics
• Subjects: Antiferromagnetism; Atomic force microscopy; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic fields; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetization; Magnetotransport phenomena, materials for magnetotransport; Manganites; Nanoparticles; Particles (of physics); Physics; Shells; Particle size; Magnetization; Magnetic cluster; Core shell structure; Magnetic field effects; Ferromagnetic-antiferromagnetic transitions; Magnetic nanomaterial; Nanoparticles; Irreversible processes; Thermoremanent magnetization; Magnetic particles; High field; Isothermal remanent magnetization; Frustration; Manganites
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/24/26/266001

Magnetic properties of interacting La0.2Ca0.8MnO3 nanoparticles have been investigated. The field-induced transition from antiferromagnetic (AFM) to ferromagnetic (FM) state in the La0.2Ca0.8MnO3 bulk has been observed at exceptionally high magnetic fields. For large particles, the field-induced transition widens while magnetization progressively decreases. In small particles the transition is almost fully suppressed. The thermoremanence and isothermoremanence curves constitute fingerprints of irreversible magnetization originating from nanoparticle shells. We have ascribed the magnetic behaviour of nanoparticles to a core-shell scenario with two main magnetic contributions; one attributed to the formation of a collective state formed by FM clusters in frustrated coordination at the surfaces of interacting AFM nanoparticles and the other associated with inner core behaviour as a two-dimensional diluted antiferromagnet.