Ultra-high sensitivity magnetic field and magnetization measurements with an atomic magnetometer

TL;DR

This paper presents an ultra-sensitive atomic magnetometer based on optically-pumped potassium atoms operating in the SERF regime, achieving record sensitivity and enabling new applications like measuring weak remnant magnetization at high temperatures.

Contribution

The paper introduces a highly sensitive atomic magnetometer with record sensitivity and demonstrates its application in measuring weak remnant magnetization at elevated temperatures.

Findings

Magnetic field sensitivity of 160 aT/Hz$^{1/2}$ achieved.

Measurement of remnant rock magnetization at temperatures up to 420°C.

Energy resolution per unit time of $44 \, \hbar$.

Abstract

We describe an ultra-sensitive atomic magnetometer using optically-pumped potassium atoms operating in spin-exchange relaxation free (SERF) regime. We demonstrate magnetic field sensitivity of 160 aT/Hz$^{1/2}$ in a gradiometer arrangement with a measurement volume of 0.45 cm$^3$ and energy resolution per unit time of $44 \hbar$. As an example of a new application enabled by such a magnetometer we describe measurements of weak remnant rock magnetization as a function of temperature with a sensitivity on the order of 10$^{-10}$ emu/cm$^3$/Hz$^{1/2}$ and temperatures up to 420$^\circ$C.