Evolution of the magnetic structure of TbRu2Al10 in applied field

• The magnetic and physical properties of the intermetallic TbRu2Al10 were examined.
• TbRu2Al10 was found to order antiferromagnetically at 15.0(3) K.
• Neutron powder diffraction revealed sinusoidal magnetic ordering below 15 K.
• Single crystal neutron diffraction revealed square wave magnetic order at 2 K.
• An applied magnetic field along the c-axis forces the moments into pulse wave order.

TbRu2Al10 is found to undergo two magnetic phase transitions as a function of temperature and three as a function of applied field at low temperature. The Tb3+ magnetic moments order antiferromagnetically along the c-axis at 15.0(3) K, with an incommensurate sinusoidally modulated structure with a propagation vector of k = (0, 0.759(1), 0). At 6.5(3) K the structure switches to square wave order. Analysis of single crystal TbRu2Al10 has revealed that this square wave structure is altered to a ‘pulse wave’ on application of a 1.30 T magnetic field along the c-axis, with two in fifty of the magnetic moments across the structure changing direction to be aligned parallel with the direction of the field. At 1.85 T a further three moments flip, leading to a duty cycle of 60% and resulting in a total change of one in ten moments from the starting square wave structure.