As the Internet of Things (IoT) becomes more integral to how we live our lives and society becomes ever increasingly connected, the need for efficient nanoscale radio frequency detection is becoming more of a pressing issue. The commonly used technique of a superheterodyne conversion of the incoming signal to an intermediate frequency (IF), requires a relatively large electronic circuit, including a local oscillator, mixer, various filters and a rectifier (i.e. diode). In order to radically simplify this process, we propose a spintronics-based nanometric single device whose resistance varies linearly as a function of the incoming frequency. This analogue frequency sensor allows a direct measurement of the incoming frequency and can work over many frequency bands and could replace a significantly larger conventional electronics circuit, thus reducing the footprint and potentially the energy cost. Three types of operation of the frequency sensor are demonstrated: a HF/VHF sensor based on a subharmonic modulation working across 9 different bands with 1-10 MHz bandwidth and 200 kHz resolution, a VHF/UHF sensor based on direct gyrotropic excitation operating between 150-225MHz with 250 kHz resolution and a UHF/SHF sensor based on indirect spin wave excitation operating between 2-4GHz with a 2.5 MHz resolution.
We present an experimental study of vortex dynamics in magnetic nanocontacts based on pseudo spin valves comprising the Co$_2$MnGe Heusler compound. The films were grown by molecular beam epitaxy, where precise stoichiometry control and tailored stacking order allowed us to define the bottom ferromagnetic layer as the reference layer, with minimal coupling between the free and reference layers. 20-nm diameter nanocontacts were fabricated using a nano-indentation technique, leading to self-sustained gyration of the vortex generated by spin-transfer torques above a certain current threshold. By …
We have conducted experiments to probe how the dynamics of nanocontact vortex oscillators can be modulated by an external signal. We explore the phase-locking properties in both the commensurate and chaotic regimes, where chaos appears to impede phase-locking while a more standard behavior is seen in the commensurate phase. These different regimes correspond to how the periodicity of the vortex core reversal relates to the frequency of core gyration around the nanocontact; a commensurate phase appears when the reversal rate is an integer fraction of the gyration frequency, while a chaotic stat…
The development of spintronic oscillators is driven by their potential applications in radio frequency telecommunication and neuromorphic computing. In this work, we propose a spintronic oscillator based on the chiral coupling in thin magnetic films with patterned anisotropy. With an in-plane magnetized disk imprinted on an out-of-plane magnetized slab, the oscillator takes a polar vortex-like magnetic structure in the disk stabilized by a strong Dzyaloshinskii-Moriya interaction. By means of micromagnetic simulations, we investigate its oscillatory properties under applied spin current and, b…
We present an experimental study of spin-torque driven vortex self-oscillations in magnetic nanocontacts. We find that above a certain threshold in applied currents, the vortex gyration around the nanocontact is modulated by relaxation oscillations, which involve periodic reversals of the vortex core. This modulation leads to the appearance of commensurate but also more interestingly here, incommensurate states, which are characterized by devil's staircases in the modulation frequency. We use frequency- and time-domain measurements together with advanced time-series analyses to provide experim…
Directional vortex pinning at microwave frequency in YBa$_{2}$Cu$_3$O$_{7-x}$ thin films with BaZrO$_3$ nanorods
研究了用脉冲激光烧蚀法从含5%（摩尔分数）BaZrO $_3$的靶上生长的YBaPDMATHABMM CuPDMATHABMN O $_{7-x}$薄膜的各向异性和定向钉扎效应. BaZrO $_3$夹杂物自组装得到沿c轴取向的纳米棒，从而为涡旋钉扎提供了优先方向。涡旋响应的方向性研究在高交流频率与复杂的微波响应在48 GHz，作为一个功能的应用领域和领域和c轴之间的角度$θ$。复杂的微波响应不表现出任何角度缩放，这表明YBa $_2$ Cu $_3$ O $_{7-x}$的结构各向异性的补充，至少另一个优选的取向。钉扎参数$r$显示定向钉扎的证据，在围绕c轴的宽范围的角度中有效（因此归因于BZO纳米柱）。
