Magnetization of the Mn${}_{1-x}$Fe${}_x$Si in high magnetic field up to 50 T: possible evidence of a field-induced Griffiths phase

Abstract

Magnetic properties of single crystals of Mn${}_{1-x}$Fe${}_x$Si solid solutions with $x<0.2$ are investigated by pulsed field technique in magnetic fields up to 50 T. It is shown that magnetization of Mn${}_{1-x}$Fe${}_x$Si in the paramagnetic phase follows power law $M(B)\sim B^{\hat{I}}\pm$ with the exponents $\hat{I}\pm \sim 0.33-0.5$, which starts above characteristic fields $B_c\sim 1.5-7$ T depending on the sample composition and lasts up to highest used magnetic field. Analysis of magnetization data including SQUID measurements in magnetic fields below 5 T suggests that this anomalous behavior may be likely attributed to the formation of a field-induced Griffiths phase in the presence of spin-polaron effects.

to be published in JETP Letters