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dc.creatorGuzmán Verri, Gian Giacomo
dc.creatorLittlewood, Peter B.
dc.description.abstractFerroelectrics are attractive candidate materials for environmentally friendly solid state refrigeration free of greenhouse gases. Their thermal response upon variations of external electric fields is largest in the vicinity of their phase transitions, which may occur near room temperature. The magnitude of the effect, however, is too small for useful cooling applications even when they are driven close to dielectric breakdown. Insight from microscopic theory is therefore needed to characterize materials and provide guiding principles to search for new ones with enhanced electrocaloric performance. Here, we derive from well-known microscopic models of ferroelectricity meaningful figures of merit for a wide class of ferroelectric materials. Such figures of merit provide insight into the relation between the strength of the effect and the characteristic interactions of ferroelectrics such as dipolar forces. We find that the long range nature of these interactions results in a small effect. A strategy is proposed to make it larger by shortening the correlation lengths of fluctuations of polarization. In addition, we bring into question other widely used but empirical figures of merit and facilitate understanding of the recently observed secondary broad peak in the electrocalorics of relaxor ferroelectrics.es_ES
dc.description.sponsorshipU.S. Department of Energy, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357es_ES
dc.rightsAtribución-NoComercial-SinDerivadas 3.0 Costa Ricaes_ES
dc.sourceAPL Materials 4, 064106 (2016)es_ES
dc.subjectrelaxor ferroelectricses_ES
dc.subjectmean field theoryes_ES
dc.titleWhy is the electrocaloric effect so small in ferroelectrics?es_ES
dc.typeartículo científico
dc.description.procedenceUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA)es_ES

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Atribución-NoComercial-SinDerivadas 3.0 Costa Rica
Except where otherwise noted, this item's license is described as Atribución-NoComercial-SinDerivadas 3.0 Costa Rica