Critical phenomenon of the layered chiral helimagnetic YbNi3Al9

Abstract

Two-dimensional layered YbNi _3 Al _9 exhibits a chiral helimagnetic ground state, which is a candidate for the field-modulated chiral magnetic soliton. In this work, the magnetism and critical phenomenon of YbNi _3 Al _9 are investigated. As H ⊥ c , a magnetic step with loop can be observed in the field-dependent magnetization, which may be corresponding to the possible chiral magnetic soliton phase transition. Based on the analysis of isothermal magnetization around T _C , the critical exponents are obtained as β = 0.1370(2), γ = 1.7955(4), and δ = 14.1043(7), which fulfill the Widom scaling relation and Rushbrooke’s law. Moreover, the obtained critical exponents are testified by the modified Arrott plot and scaling hypothesis. The critical exponents of YbNi _3 Al _9 are close to the theoretically prediction of 2D-Ising model with the spatial-dimensionality n = 2 and spin-dimensionality d = 1, indicating one-dimensional magnetic coupling in the two-dimensional framework. Based on universality scaling, we construct the detailed H – T phase diagram around the phase transition with H ⊥ c , which reveals that the field-induced magnetic transition for H ⊥ c is of the first-order type.

Keywords

• critical phenomenon
• magnetic entropy change
• critical exponent
• scaling
• phase diagram