Magnetization of Mn 1– x Fe x Si in high magnetic fields up to 50 T: Possible evidence of a field-induced Griffiths phase

Magnetic properties of single crystals of Mn1–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 Mn1–x Fe x Si in the paramagnetic phase follows power law with the exponents M(B) ~ B α, which starts above characteristic fields B c ~ 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.