AI 中文总结
本研究通过调控NiFe合金薄膜的磁弹系数符号，实现了磁声衰减非互易性的反转，确立非互易性可作为磁弹耦合的纳米尺度探针。
AI 中文摘要
非互易性是输运过程的不对称性，是二极管到微波隔离器等技术的基础。在铁磁体中，表面声波会产生传播手性固定的椭圆有效场，打破其传播的非互易性。尽管对该现象已有数十年研究，但控制非互易性符号的方法仍未实现。本研究在NiₓFe₁₀₋ₓ薄膜中观测到符号反转：在坡莫合金零磁致伸缩组分处，仅0.8 at.%的成分变化就使磁弹系数b的符号发生反转，进而使椭圆有效场的手性反转，非互易性从78.6%变为-61.8%。角依赖测量和自旋波-椭圆度模型表明，b符号反转会改变椭圆偏振有效场的手性；结合三次方频率标度，在10 nm薄膜中可将b的符号分辨至-0.05 MPa，确立非互易性作为磁弹耦合的纳米尺度探针的作用。
英文摘要
Nonreciprocity, the asymmetry of transport, underlies technologies from the diode to the microwave isolator. In a ferromagnet, a surface acoustic wave generates an elliptical effective field with propagation-locked handedness, breaking the reciprocity of its propagation. Despite decades of study on this phenomenon, a method for controlling the sign of the nonreciprocity has remained elusive. Here we observe a sign reversal in Ni$_x$Fe$_{100-x}$ films. A 0.8 at.% change across Permalloy's zero-magnetostriction composition, where the magnetoelastic coefficient $b$ changes sign, reverses the handedness of the elliptical effective field and thereby the nonreciprocity, from 78.6% to -61.8%. Angle-dependent measurements and spin-wave-ellipticity modelling show that reversing the sign of $b$ reverses the handedness of the elliptically polarized effective field. Aided by cubic frequency scaling, we resolve the sign of $b$ down to -0.05 MPa in a 10-nm film, establishing nonreciprocity as a nanoscale probe of magnetoelastic coupling.
Comments13 pages, 4 figures
