摘要:

Unique insight into the nature of ferroelectricity is emerging from the study of Langmuir-Blodgett films of vinylidene fluoride copolymers. These films are the first truly two-dimensional ferroelectrics, with thickness-independent bulk ferroelectric properties and a separate surface phase transition. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1324474

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

More than a decade ago computer simulations based on Gordon-Kim potentials suggested thatNaCaF3would be a ferroelectric compound if it could be formed experimentally. Recent attempts to form thin films ofNaCaF3using pulsed-laser deposition have prompted us to carry out further theoretical studies of this material. Here we apply the self-consistent atomic deformation method to calculate electronic, structural and vibrational properties ofNaCaF3and the constituent compounds NaF andCaF2.©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1324475

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Multiferroic magnetoelectrics are materials which are both ferromagnetic and ferroelectric in the same phase. As a result they have a spontaneous magnetization which can be switched by an applied magnetic field, a spontaneous polarization which can be switched by an applied electric field, and often some coupling between the two. Very few exist in nature, or have been synthesized in the laboratory. In this paper we explore the fundamental physics behind the scarcity of ferromagnetic ferroelectric coexistence, and examine the properties of some known magnetically ordered ferroelectric materials. We find that in general the transition metaldelectrons, which are essential for magnetism, reduce the tendency for off-center ferroelectric distortion. Consequently, an additional electronic or structural driving force must be present for ferromagnetism and ferroelectricity to occur simultaneously. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1324476

出版商:AIP    

年代:1900

数据来源: AIP