Vu N M, Luo X, Novakov S, Jin W, Nordlander J, Meisenheimer P B, Trassin M, Zhao L, Heron J T
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
Sci Rep. 2020 Sep 7;10(1):14721. doi: 10.1038/s41598-020-71619-1.
The manipulation of antiferromagnetic order in magnetoelectric CrO using electric field has been of great interest due to its potential in low-power electronics. The substantial leakage and low dielectric breakdown observed in twinned CrO thin films, however, hinders its development in energy efficient spintronics. To compensate, large film thicknesses (250 nm or greater) have been employed at the expense of device scalability. Recently, epitaxial VO thin film electrodes have been used to eliminate twin boundaries and significantly reduce the leakage of 300 nm thick single crystal films. Here we report the electrical endurance and magnetic properties of thin (less than 100 nm) single crystal CrO films on epitaxial VO buffered AlO (0001) single crystal substrates. The growth of CrO on isostructural VO thin film electrodes helps eliminate the existence of twin domains in CrO films, therefore significantly reducing leakage current and increasing dielectric breakdown. 60 nm thick CrO films show bulk-like resistivity (~ 10 Ω cm) with a breakdown voltage in the range of 150-300 MV/m. Exchange bias measurements of 30 nm thick CrO display a blocking temperature of ~ 285 K while room temperature optical second harmonic generation measurements possess the symmetry consistent with bulk magnetic order.
利用电场调控磁电材料CrO中的反铁磁序因其在低功耗电子学方面的潜力而备受关注。然而，在孪晶CrO薄膜中观察到的大量漏电和低介电击穿现象阻碍了其在节能自旋电子学中的发展。为了弥补这一问题，人们采用了较大的薄膜厚度（250纳米或更大），但这是以牺牲器件可扩展性为代价的。最近，外延VO薄膜电极已被用于消除孪晶界，并显著降低300纳米厚单晶薄膜的漏电。在此，我们报道了在外延VO缓冲的AlO(0001)单晶衬底上生长的薄（小于100纳米）单晶CrO薄膜的电耐久性和磁性能。在同结构的VO薄膜电极上生长CrO有助于消除CrO薄膜中孪晶畴的存在，从而显著降低漏电流并提高介电击穿。60纳米厚的CrO薄膜显示出类似体材料的电阻率（约10Ω·cm），击穿电压在150 - 300 MV/m范围内。对30纳米厚CrO进行的交换偏置测量显示其阻塞温度约为285 K，而室温光学二次谐波产生测量结果显示其对称性与体磁序一致。
