Magnetization by rotation and gyromagnetic gyroscopes

We discuss how the general phenomenon of magnetization by rotation may be used to probe the angular velocity of the laboratory with respect to a local frame of inertia. We show that a gyroscope with no moving parts based on this phenomenon has to include a sensor and a shield with different magnetomechanic factors. This is necessary in order to suppress the sensitivity to a magnetic field without canceling the effect of rotation. We present a realization of the gyroscope where the magnetization of a ferromagnetic rod is measured by a superconducting quantum interference device (SQUID). The rod is rigidly held in the interior of a closed superconducting shield. Because of the difference between the spin magnetomechanic factor of the magnetic rod {γ}=m/e, with m and e respectively the electron mass and charge, and the orbital magnetomechanic factor of Cooper pairs in the shield {γ}=2m/e, the SQUID output is linear in the absolute angular velocity of the device. By contrast, in the limit of perfect shielding, it turns out to be insensitive to magnetic fields. We experimentally demonstrate the principle of operation of this device.