Pressure dependence of the magnetic structures and excitations in the giant magnetostriction compound TbCu2
作者:M Rotter、M Doerr、M Loewenhaupt、W Kockelmann、R.I Bewley、R.S Eccleston、A Schneidewind、G Behr
DOI:10.1016/s0304-8853(03)00633-4
日期:2004.3
A small shift of magnetic excitation energies is expected when applying pressure on a compound with large magnetostriction. We were able to observe these tiny shifts by inelastic neutron scattering on the giant magnetostriction (GMS) compound TbCu2. The experiments were performed at 4 and 60 K using a McWhan pressure cell. The peaks in the spectra were shifted by 0.4meV to higher energies at the maximum pressure of 2GPa by the magnetoelastic interaction. This strong interaction of the crystal electric field (CF) with the lattice may be liable for the GMS effect. Moreover, neutron diffraction experiments show a weak but noticeable influence of strong external pressure on the magnetic structure of TbCu2. The ambient pressure magnetic propagation vector tau = (2/3 10) at low temperatures is also preserved under pressure. The data indicate a non-collinear magnetic structure. In addition to the CF the exchange interaction also changes under pressure and leads to a slightly modified magnetic propagation vector in the vicinity of T-N. (C) 2003 Elsevier B.V. All rights reserved.