Magnetic excitations in Mn3Al2Ge3O12

We propose to measure the spectrum of magnetic excitations in a single crystal sample of Mn3Al2Ge3O12, a 120-degrees triangular antiferromagnet on a hyper-kagome lattice. The three main aspects of the proposal are: (i) to establish the positions and the intensity of the spin-wave branches in zero field in the magnetically ordered state (well below the TN=6.5 K); (ii) to follow the excitations spectrum as a function of magnetic field applied along the (100) axis for which a spin-reorientation is expected at 20 kOe; (iii) to probe the excitations spectrum above the TN in search for the signs for a “hidden order”.