title: Highly sensitive nanoscale spin-torque diode.
abstract: Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4 mV mW(-1)). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000 mV mW(-1) is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800 mV mW(-1)). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases.
authors.affiliation: 1] Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan [2].
authors.forename: S
authors.initials: S
authors.lastname: Miwa
authors.affiliation: 1] Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan [2] National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan [3].
authors.forename: S
authors.initials: S
authors.lastname: Ishibashi
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tomita
authors.affiliation: 1] Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan [2] National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Tamura
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Mizuochi
authors.affiliation: 1] National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan [2].
authors.forename: T
authors.initials: T
authors.lastname: Saruya
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kubota
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yakushiji
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Imamura
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Fukushima
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yuasa
authors.affiliation: 1] Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan [2] National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki