Field-induced magnetic phase transitions in a GdSi single crystal

We report on unusual field-induced magnetic phase transitions observed in a GdSi single crystal at low temperature. The magnetization curves initially show an anisotropic character between the b axis and the $ac$ plane. With increasing applied field, the magnetization measured along the c axis merges with that measured along the b axis through a jumplike transition at field of about 2.50.3em0exT, whereas that measured along the a axis gradually joins the other two at about 3.80.3em0exT. Above 3.80.3em0exT, the magnetization behaves isotropically with applied magnetic field and then reaches saturation through a jumplike transition at a field of about 19.50.3em0exT. We discuss the anomalous behavior of the compound in terms of interplay between the localized $4f$ spins and the (itinerant) conduction electrons.