Progress toward a precessing ferromagnetic needle magnetometer for ultrasensitive torque measurements

ORAL

Abstract

A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω when IΩ << Nħ, where I is the moment of inertia of the needle and N is the number of polarized spins in the needle. In this regime the needle behaves as a gyroscope with spin Nħ maintained along the easy axis of the needle by the crystalline and shape anisotropy. If the needle is sufficiently isolated from the environment, a measurement of precession can yield sensitivity to torques well beyond that of existing techniques. Levitation of a micron-scale ferromagnetic particle above a superconductor is one possible method of near frictionless suspension enabling observation of ferromagnetic needle precession and ultrasensitive torque measurements. We discuss experimental investigations of the dynamics of a micron-scale ferromagnetic particle levitated above a superconducting niobium surface with this goal in mind.

*This work was supported by the Simons and Heising-Simons Foundations and a grant from the DFG through the DIP program (FO703/2-1). DFJK acknowledges the support of the U.S National Science Foundation under grant No. PHY-1707875.

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Presenters

  • Derek F Jackson Kimball

    • California State University, East Bay

Authors

  • Tao Wang

    • University of California, Berkeley

  • Sean Lourette

    • University of California, Berkeley

  • Sean R O'Kelley

    • University of California, Berkeley

  • Matin Kayci

    • University of California, Berkeley

  • Yehuda Benzion Band

    • Ben-Gurion University of the Negev

  • Dmitry Budker

    • Helmholtz Institute, JGU Mainz and University of California, Berkeley, Helmholtz Institute, Johannes Gutenberg University
    • University of California, Berkeley, Helmholtz Institute at Gutenberg University, Mainz, Germany

  • Derek F Jackson Kimball

    • California State University, East Bay

  • Alexander Sushkov

    • Boston University