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

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 with the exponents $M(B) \sim B^{\alpha}$, 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.
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