Effect of uniaxial pressure on helimagnetic structure in Lu2Fe17

The incommensurate helimagnetic structure IHS in the Lu2Fe17 intermetallics has been induced at 5 K by hydrostatic pressure above 0.3 GPa and characterized by a propagation vector 00tz . The observed dependence of tz on external variables is discussed within a simple model based on a complex dependence of exchange interactions Jn,m n, m f, j, k and g on distances between Fe atoms in inequivalent positions 4f, 12j, 12k and 6g of the hexagonal P63 mmc crystal structure. To verify this model, we have studied magnetization and representative neutron reflections of Lu2Fe17 single crystals under high hydrostatic pressure and uniaxial compression with stress amp; 963; a axis and amp; 963; c axis. Both, the metamagnetic transitions and magnetic satellites of the 00tz type that verify the presence of IHS in Lu2Fe17 at 5 K were observed under hydrostatic pressure and under uniaxial stress amp; 963; c axis only. We show that the dominant role in an appearance of IHS in the Lu2Fe17 under compression is played by the Jff and Jfj exchange interactions