四类畴压电压磁超晶格的电磁波单方向透射
Unidirectional Transmission Investigations of Electromagnetic Waves in Piezoelectric-Piezomagnetic Superlattices with Four Types of Domains in a Unit Cell

压电压磁超晶格中畴排列方式的不同导致其性质发生改变. 文中基于四类畴压电压磁超晶格结构，将1个周期内畴的排布方式分为（+P,-P,+M,-M）、（+P,-P,+P,+M）和（+P,+M,-M,+M）3种. 对于（+P,－P,+P,-M）结构，〖AKω-D9〗=2719附近存在1个单方向频率通道，相对带宽约为326%. 对于（+P,－P,+P,+M）结构，〖AKω-D9〗=2374附近通道2的最大群速度指数可达ng=69 6951. 电磁波通过长为1 cm的超晶格的延迟时间约为232 μs. 对于（+P,+M,－M,+M）结构，通过外加电场反转极化可实现快波和慢波的切换，群速度指数的改变量可达525, 可用于构造单方向电磁波导和群速度延迟器件.
： The different arrangements of domains of piezoelectric-piezomagnetic superlattices lead to different pro-perties. Piezoelectric-piezomagnetic superlattices with four types of domains in a unit cell (FPPS) are studied in detail in this work; the arrangements of a period are divided into 3 types, that is (+P,-P,+M,-M), (+P,-P,+P,〖JP2〗+M) and (+P,+M,-M,+M). For the FPPS with 〖JP2〗(+P,-P,+M,-M) domains, there is a frequency channel allowing one-way transmission of forward electromagnetic waves, and the relative bandwidth is about 326%. For the FPPS with (+P,－P,+P,+M),〖JP〗 the maximum group velocity index ngreaches 69 6951 in the frequency channel around ω〖DD(-1.7mm〗-〖DD)〗=2374. The delay time is about 232 μs when electromagnetic waves pass through the FPPS with the total length of 1 cm. For the FPPS with (+P,+M,－M,+M), the fast and slow waves can be switched when the electric field is applied to invert the polarization, and the change of group velocity index can reach 525. Thus, it is suggested that the FPPS can be applied to construct the one-way waveguide and slow wave delay devices