Eur. Phys. J. D 38, 445-454 (2006)
https://doi.org/10.1140/epjd/e2006-00052-0

Relaxation of spin polarized ³He by magnetized ferromagnetic contaminants

Part III

¹ Institut für Physik, 55099 Mainz, Germany
² Physikalisch-Technische Bundesanstalt, 10587 Berlin, Germany
³ Schott AG, Mainz, Germany

Corresponding authors: ^a wheil@mail.uni-mainz.de - ^b ernst.otten@uni-mainz.de

Received: 26 August 2005
Revised: 19 December 2005
Published online: 14 March 2006

Abstract

In the first in a series of three papers on wall relaxation of spin polarized ³He we have reported on a breakdown of relaxation times which is observed after exposing the ³He containing glass cells to a strong magnetizing field. In this third paper we give a quantitative analysis of this phenomenon, based on magnetic signal detection by means of SQUIDs, on the pressure dependence of relaxation times in magnetized cells, as well as on Monte Carlo simulations of ³He-relaxation in a macroscopic dipole field. Our analysis allows to identify the contaminants as being aggregates of dust-like Fe₃O₄ particles (magnetite) with a radius m and a remanent magnetic moment of the order of m ≈O(10A m²). The particles are located at or close to the inner glass surface.