High-Power Coherent Microwave Emission from Magnetic Tunnel Junction Nano-oscillators with Perpendicular Anisotropy

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• 作者：Zhongming Zeng ; Pedram Khalili Amiri ; Ilya N. Krivorotov ; Hui Zhao ; Giovanni Finocchio ; Jian-Ping Wang ; Jordan A. Katine ; Yiming Huai ; Juergen Langer ; Kosmas Galatsis ; Kang L. Wang ; HongWen Jiang
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：July 24, 2012
• 年：2012
• 卷：6
• 期：7
• 页码：6115-6121
• 全文大小：436K
• 年卷期：v.6,no.7(July 24, 2012)
• ISSN：1936-086X

文摘

The excitation of the steady-state precessions of magnetization opens a new way for nanoscale microwave oscillators by exploiting the transfer of spin angular momentum from a spin-polarized current to a ferromagnet, referred to as spin-transfer nano-oscillators (STNOs). For STNOs to be practical, however, their relatively low output power and their relatively large line width must be improved. Here we demonstrate that microwave signals with maximum measured power of 0.28 渭W and simultaneously narrow line width of 25 MHz can be generated from CoFeB鈥揗gO鈥揵ased magnetic tunnel junctions having an in-plane magnetized reference layer and a free layer with strong perpendicular anisotropy. Moreover, the generation efficiency is substantially higher than previously reported STNOs. The results will be of importance for the design of nanoscale alternatives to traditional silicon oscillators used in radio frequency integrated circuits.

Keywords:

spin-transfer nano-oscillators; microwave; magnetic tunnel junction; perpendicular anisotropy; magnetoresistance