Multiferroic composite thinfilms of ferroelectrics and magnets have attracted ever-increasing interest in most recent years.In this review,magnetoelectric(ME)responses as well as their underlying ME coupling mechanisms in such multiferroic composite thinfilms are discussed,oriented by their potential applications in novel ME devices.Among them,the direct ME response,i.e.,magnetic-field control of polarization,can be exploited for micro-sensor applications(sensing magneticfield,electric current,light,etc.),mainly determined by a strain-mediated coupling interaction.The converse ME response,i.e.,electric-field modulation of magnetism,offers great opportunities for new potential devices for spintronics and in data storage applications.A series of prototype ME devices based on both direct and converse ME responses have been presented.The review concludes with a remark on the future possibilities and scientific challenges in thisfield.
A new class of media with abnormal electromagnetic parameters has been attracting increasing attention because of its exotic properties and potential application.Currently,typical metamaterials are mainly composed of artificially designed metallic periodic structures.However,due to the limitations of available fabrication technologies,physical size and material effects,it is difficult to realize these abnormal properties by these artificial structures in the high-frequency regime.Therefore,it is important to find materials with intrinsic abnormal electromagnetic responses.In this field,a new mechanism based on the interaction between polar lattice vibrations and electromagnetic waves has been proposed.In this paper,we review progress in this field.
High performance low temperature co-fired ceramic(LTCC)dielectrics is highly desired for next generation information technology.The rational design is a key issue for the development of new LTCC materials.In comparison to the design of conventional electroceramics,more attention should be paid on the formation process of the material structure for that of LTCC,in addition to the physical properties,due to the special requirement in fabrication processing.In this paper,sintering mechanism of three types of LTCC materials,i.e.,glass-ceramics,glass ceramic composite,and glass bonded ceramics,as well as important factors of their dielectric properties are discussed and summarized,and the design strategies for LTCC dielectrics,based on new matrix materials with much lower sintering temperature or higher quality,are proposed.As an example for rational design,oxyfluoride glass-ceramic based dielectrics,a new class of LTCC materials with lowεr,is analyzed.
