Magnetic nano/microrotors are passive elements spinning around an axis due to an external rotating field while remaining confined to a plane. They have been used to date in different applications related to fluid mixing, drug delivery, or biomedicine. Here we realize an active version of a magnetic microgyroscope which is simultaneously driven by a photoactivated catalytic reaction and a rotating magnetic field. We investigate the uplift dynamics of this colloidal spinner when it precesses around its long axis while self-propelling due to the light induced decomposition of hydrogen peroxide in water. By combining experiments with theory, we show that activity emerging from the cooperative action of phoretic and osmotic forces effectively increases the gravitational torque, which counteracts the magnetic and viscous ones, and carefully measure its contribution. Finally, we demonstrate that by modulating the field amplitude, one can induce hysteresis loops in the uplift dynamics of the spinners.

中文翻译：

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具有活性可调岁差动力学的光催化磁性微型陀螺仪


磁性纳米/微转子是由于外部旋转场绕轴旋转的无源元件，同时仍然局限于平面。迄今为止，它们已用于与流体混合、药物输送或生物医学相关的不同应用。在这里，我们实现了磁性微型陀螺仪的有源版本，它同时由光激活催化反应和旋转磁场驱动。我们研究了这种胶体旋转器在绕长轴进动时由于光诱导的过氧化氢在水中分解而自行推进时的升力动力学。通过将实验与理论相结合，我们表明，由水力和渗透力的协同作用产生的活动有效地增加了重力扭矩，从而抵消了磁性和粘性扭矩，并仔细测量了其贡献。最后，我们证明，通过调制场振幅，可以在旋转器的隆起动力学中诱导磁滞回线。