Simulation of the magnetocaloric effect in Tb nanofilms

Journal Article · Mon Mar 31 00:00:00 EDT 2014 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4870199· OSTI ID:22265948

Mello, Vamberto D. ^[1]; Vasconcelos, Manoel S. ^[2]

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1. Departamento de Física,Universidade do Estado do Rio Grande do Norte (UERN), Mossoró-RN (Brazil)
2. Escola de Ciência e Tecnologia (ECT), Universidade Federal do Rio Grande do Norte (UFRN), Natal-RN (Brazil)

Rare-earth (RE) metals have different magnetic structures resulting from the competition between the crystal-field and exchange interactions. When a magnetic field is applied it creates a third interaction and the magnetic structures are more complicated. In thin films, it is expected that even the magnetic arrangement itself can be strongly modified. Rare-earth helimagnets such as Terbium (Tb), Holmium (Ho) and Dysprosium (Dy) represent the best candidates to evidence such finite-size effects. This finite-size effect is caused by the reduced number of atoms in the direction perpendicular to the film plane that leads to a decrease of the total magnetic exchange energy. We report this contribution to the investigation of magnetocaloric effect (MCE) of thin Terbium films in the helimagnetic temperature range, from T{sub C} = 219 K to T{sub N} = 231 K, for external fields of the order of 1 kOe. We find that for strong fields, H = 50 kOe, the adiabatic temperature change ΔT near the Néel temperature is around 15 K for any thickness of Tb films. However large thickness effects are found for small values of the magnetic field. For field strength of the order of a few kOe, the thermocaloric efficiency increases significantly for ultrathin (nanomagnetic) films.

• OSTI ID: 22265948
• Journal Information: AIP Conference Proceedings, Vol. 1590, Issue 1; Conference: International conference on electronic, photonic, plasmonic and magnetic properties of nanomaterials, London (Canada), 12-16 Aug 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
COMPETITION
CRYSTAL FIELD
DYSPROSIUM
EFFICIENCY
EXCHANGE INTERACTIONS
HOLMIUM
MAGNETIC FIELDS
MAGNETIC PROPERTIES
SIMULATION
TEMPERATURE RANGE
TERBIUM
THERMODYNAMIC PROPERTIES
THICKNESS
THIN FILMS