Eur. Phys. J. B (2013) 86: 104
https://doi.org/10.1140/epjb/e2013-30673-7

Regular Article

Room temperature magnetism in MB₆ (M = Ca, Sr, Ba) films grown by pulsed laser deposition^*

School of Physics and CRANN, Trinity College, Dublin 2, Ireland

^a e-mail: acklandk@tcd.ie

Received: 24 July 2012
Received in final form: 4 January 2013
Published online: 20 March 2013

Abstract

Room temperature magnetism is reported in amorphous MB₆ (M = Ca, Sr, Ba) films grown by pulsed laser deposition; these materials contain no d or f electrons normally associated with magnetic ordering. The magnetism is virtually anhysteretic, isotropic, temperature independent from 4 − 300 K and saturates quickly (<0.3 T) with applied field. It is shown that ferromagnetic impurities cannot account for the magnitude of the larger magnetic signals measured. The magnetism is thought to be due to a defect-based impurity band, which can become spin split and result in high temperature Stoner ferromagnetism when the density of states at the Fermi level is sufficiently high. The magnetic signals correspond to an average film magnetization in the range 10 − 100 kA m^-1, but from analysis of the variation of the magnetic moment with film thickness, it is shown that the magnetism originates mainly near the interface with the substrate.