Meisenheimer P B, Steinhardt R A, Sung S H, Williams L D, Zhuang S, Nowakowski M E, Novakov S, Torunbalci M M, Prasad B, Zollner C J, Wang Z, Dawley N M, Schubert J, Hunter A H, Manipatruni S, Nikonov D E, Young I A, Chen L Q, Bokor J, Bhave S A, Ramesh R, Hu J-M, Kioupakis E, Hovden R, Schlom D G, Heron J T
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA.
Nat Commun. 2021 May 12;12(1):2757. doi: 10.1038/s41467-021-22793-x.
Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare-earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. FeGa alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC FeGa alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A FeGa - [Pb(MgNb)O]-[PbTiO] (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10 s m. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.
磁致伸缩材料可转换磁能和机械能，与压电元件结合时，可实现用于高灵敏度磁场传感器和超越互补金属氧化物半导体（CMOS）技术的节能型磁电转换。缺乏具有高磁致伸缩系数的韧性无稀土材料促使人们去发现性能更优的材料。铁镓合金是性能最佳的无稀土磁致伸缩材料之一；然而，由于形成了寄生有序金属间相，当镓含量超过x = 19%时，磁致伸缩会急剧受到抑制。在此，我们利用外延生长将体心立方（BCC）铁镓合金的稳定性扩展到镓含量高达x = 30%的情况，这样做相对于块体材料，磁致伸缩显著提高了多达10倍，比传统的稀土基磁致伸缩材料大2倍。一种铁镓-[铅镁铌酸铅]-[钛酸铅]（PMN-PT）复合磁电材料展现出稳健的90°磁各向异性电开关特性以及2.0×10 s/m的逆磁电系数。经过优化缩放后，这种高系数意味着每比特约80阿焦耳的稳定开关。
