Crystal field excitations and spin wave investigation in NdPt2B11

NdPt2B crystallizes in a non-centrosymmetric hexagonal structure. Resistivity, specific heat and susceptibility data reveal three antiferromagnetic transitions at TN1 = 19.5 K, TN2 = 11 K, and a first-order transition at Tm = 9.5 K. Our neutron diffraction study on powder and single crystal samples (with B-11) using D20 and WISH instruments revealed an original ground state. It can be represented as a superposition of three unharmonic spin density waves, combining k=(0,0,1/5), 2k=(0,0,2/5) and k=0 components at 2K, with moments polarized within the (ab)-plane and forming 60- and 120-degrees configuration. The stacking of the moments along the c-axis with the moment direction along the in-plane easy axes of the spin density waves. Interesting the magnetization isotherm for H//a-axis at 2 K and below 2 T exhibits multiple magnetization plateau (five metamagnetic transitions) and saturates above it. It is important to investigate the role of the single ion CEF anisotropy on the magnetic structure and how the spin wave excitations changes across three magnetic transitions. We, therefore, proposed to carry inelastic neutron scattreing investigations on NdPt2B powder sample to investigate the CEF and spin wave energy scale.