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Title: Simulation of the magnetocaloric effect in Tb nanofilms

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 formore » ultrathin (nanomagnetic) films.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Departamento de Física Teórica e Experimental (DFTE), Universidade Federal do Rio Grande do Norte (UFRN), Natal-RN (Brazil)
  2. Departamento de Física,Universidade do Estado do Rio Grande do Norte (UERN), Mossoró-RN (Brazil)
  3. Escola de Ciência e Tecnologia (ECT), Universidade Federal do Rio Grande do Norte (UFRN), Natal-RN (Brazil)
Publication Date:
OSTI Identifier:
22265948
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1590; Journal 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)
Country of Publication:
United States
Language:
English
Subject:
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