Neutron diffraction study on the unusual step-like phase transition in Tb-Y alloy with long-period helix antiferromagnetic structure

Recently, we found a step-like magnetization curve for Tb-0.3Y below 5 K. The sample show helix antiferromagnetic at ground state, but jumps at critical magnetic field of 1.5T, 2.1T, 2.8T, 3.0T, and 4.0T with gradually decreased intervals in the virgin M-H curve, and finally transforms to ferromagnetic state with stronger field. Such as step-like phase transition has rarely been reported, which may represent a new type of physical mechanism of phase transition. In this proposal, we aim to carry magnetic field-resolved neutron diffraction experiment at WISH to uncover the mystery.