Magnetocaloric Effect
Mostrando 13-24 de 28 artigos, teses e dissertações.
-
13. Metodos baseados na fotoacustica para caracterização de materiais magnetocaloricos / Methods based on the photoacoustic for characterization of magnetocaloric materials
In this work the photoacoustic technique was used to develop experimental setups to investigate magnetocaloric materials, which have been of great interest due to their applications in refrigeration systems. The value (4,5 ± 0,2).10-6 m2/s was determined, at room temperature, as the thermal di usivity of the Gd, based on the two-beam photoacoustic method, b
Publicado em: 2008
-
14. Th e anisotropic magnetocaloric effect in RAl2 (R=Dy, Er, Ho, Nd, Tb) compounds. / O efeito magnetocalórico anisotrópico nos compostos RAl2 (R = Dy, Er, Ho, Nd, Tb)
SOUSA, Vinícius da Silva Ramos de. O efeito magnetocalórico anisotrópico nos compostos RAl2 (R = Dy, Er, Ho, Nd e Tb). 2008. 99f. Dissertação (Mestrado em Física) - Instituto de Física Armando Dias Tavares, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 2008. O efeito magnetocalórico é a base da refrigeração magnética. O potencial magn
Publicado em: 2008
-
15. Estudo do efeito magnetocalórico através do acoplamento entre as redes cristalinas e magnéticas: uma extensão do modelo de Bean-Rodbell. / The study of magnetocaloric effect through the coupling between crystalline and magnetic lattice: an extention of the model Bean-Rodbell.
SILVA, Carla de Mello. Estudo do efeito magnetocalórico através do acoplamento entre as redes cristalina e magnética: uma extensão do modelo de Bean-Rodbell. 2008. 91f. Dissertação (Mestrado em Física) Instituto de Física, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 2008. Neste trabalho, apresentamos um estudo do efeito magnetocalórico
Publicado em: 2008
-
16. Propriedades magneticas de filmes de ligas GD-Cr / Magnetic properties of Gd-Cr alloy films
Vapor condensation techniques are very useful for preparation of alloys whose components have no mutual solubility under equilibrium conditions In this work, one of these techniques ? sputtering ? has been used to fabricate metastable GdXCr1-X alloys whose magnetic properties were investigated as a function of the Gd concentration, x. Grazing incidence angle
Publicado em: 2008
-
17. O efeito magnetocalórico nas ligas Heusler Ni54[Mn(1-x)Fex]19Ga27
In this work, magnetic entropy change of nonstoichiometric Ni54[Mn(1-x)Fex]19Ga27 Heusler alloys was experimentally verified by partial substitution (up to 50%) of the Mn atoms by magnetic Fe atoms. Such study was mainly concentrated in the magneto-structural transformation region, at low temperatures. The analysis of X-ray diffraction patterns indicate that
Publicado em: 2008
-
18. Platô na magnetização e efeito magnetocalórico na cadeia diamante cineticamente frustrada. / Magnetization plateau and magnetocaloric effect in the kinetically frustrated diamond chain.
O estudo de sistemas frustrados de spin continua sendo objeto de intensas pesquisas, em particular em baixas dimensões onde os efeitos das flutuações quânticas são mais intensos, levando a ricos diagramas de fase. Alguns sistemas de spins de baixa dimensionalidade, especialmente os unidimensionais, respondem descontinuamente às variações do campo mag
Publicado em: 2008
-
19. Estudo do efeito magnetocalórico nos sistemas Gd(Al1-xNix)2 e RMg2 (R=Pr, Dy, Er, Nd) / Systems magnetic caloric Gd(Al1-xNi)2 and RMg2, where R= Pr,Nd,Dy, and Er
Nesse trabalho investigamos as propriedades magnéticas de sistemas intermetálicos com terras-raras. Foi dado ênfase as grandezas magnetocalóricas ΔS (variação isotérmica da entropia) e ΔTad (variação adiabática da temperatura) que ocorrem com a variação do campo magnético externo. Para o sistema Gd (Al1-x Nix)2 foi feito um estudo teó
Publicado em: 2007
-
20. Structural and magnetic study of the MnAs magnetocaloric compound
The temperature induced phase transition in MnAs is analyzed in this work using X ray Rietveld refinement. The results show the presence of the hexagonal phase (P6(3)/mmc) at room temperature and the first-order structural-magnetic transition to the orthorhombic phase (Pnma) around 318 K was followed in detail. The MnAs magnetic characterization allowed to o
Materials Research. Publicado em: 2006-03
-
21. Theoretical calculus of magnetocaloric effects of La(FexSi1-x)13. / Cálculo teórico do efeito magnetocalórico do composto La(FexSi1-x)13.
The study of the magnetocaloric effect of the compound La(FexSi1-x)13 became very important, once recent experiments revealed that this compound exhibits great values of the isothermal entropy change (Δ S) and the adiabatic temperature change(ΔTad), which are the quantities used to characterize the power of refrigeration of any compound. We studied
Publicado em: 2006
-
22. Estudo de propriedades estruturais, magneticas e magnetocaloricas de compostos a base de Gd, Ge e Si / Study of structural, magnetic and magnetocaloric properties of Gd, GE e Si based compounds
This work presents the results from structural, magnetic and magnetocaloric studies about some compounds based on Gd, Ge and Si. Structural studies include optical and electronic microscopy analyses, besides X-ray diffraction. Magnetic analyses are limited to measurements of magnetization as a function of temperature and magnetic field. Using these technique
Publicado em: 2006
-
23. The study of the magnetocaloric effect in compounds of MnAs1-xAx, A = P, Sb, Te e Mn1-xFexAs / Estudo do efeito magnetocalorico em compostos de MnAs1-xAx, A = P, Sb, Te e Mn1-xFexAs
In this work we describe the obtaining processes of the MnAs1-x Ax (A= Te, P, Sb) and Mn1-xFexAs series for several concentrations. We divided this work in two stages: in the first one the samples were obtained using a high pressure furnace and in the second one using a resistive furnaces with the samples sealed in quartz tubes. The first stage, can be split
Publicado em: 2006
-
24. Magnetocaloric effect in UM2 and (U,R)Ga2 compounds / Estudo do efeito magnetocalorico em compostos UM2 e (U,R)Ga2
In this work we study the magnetocaloric effect in UM2 (M=Ga, Ge, Fe, Ni), U(Gal-xMx)2 and (Ul-yRy)Ga2 (M=AI, Ge, Si, Fe, Ni, Co, Pt and R=Dy, Er) which are ferromagnetic systems. The formation of the local moment in the UM2 ferromagnetic compound is important to obtain larger values for D S and D T. We calculated the magnetic properties and the EMC for UGa2
Publicado em: 2006