Eur. Phys. J. B 22, 3-10 (2001)
https://doi.org/10.1007/PL00011132

On the nonequilibrium light-induced diamagnetism

Institute of Physics, University of Rzeszów Al. Rejtana 16A, 35-310 Rzeszów, Poland

Corresponding author: ^a tralle@univ.rzeszow.pl

Received: 7 November 2000
Published online: 15 July 2001

Abstract

A new interpretation of light-induced magnetization changes of a magnetic semiconductor, manganese arsenide (MnAs), observed by the authors of references [1,2], is proposed in this paper. Contrary to references [1,2], where the results of experiments were interpreted as the observation of light-induced phase transition, here we propose a completely different approach. It suggests that at least far from the vicinity of T_c, there are no real magnetization changes as in case of phase transition, but there are changes of the magnetic flux threading the MnAs-sample. These changes are due to non-equilibrium light-induced diamagnetic moments of quasi-free electrons of narrow d-subbands of the MnAs-conduction band. The other aspects of the experiments of [1,2] are also discussed and some similarity between this effect and the orbital diamgnetism due to persistent currents in mesoscopic structures is emphasised.