Uni-axial dependence of hidden ordering in URuSi

Kambe, Shinsaku  ; Aoki, Dai*; Salce, B.*; Braithwaite, D.*; Flouquet, J.*; Brison, J. P.*

1 axis of the order transition temperature T0 in which URuSi hid, and the antiferromagnetic order TN. It experimented about pressure dependence. Quality single crystal 2 (a axis) 2(c axis) 4.2(a axis) mm was used. Hidden order and antiferromagnetic order transition. In order to detect, the thermal expansion coefficient was measured using the string gauge. 1 axis pressure is Sis who can change pressure continuously at low temperature using helium gas. Tem is used and it is measurement to [100] direction (direction of 4.2 mm of a axes) 5 kbar. It carried out. Under hydrostatic pressure, although TN appeared from about 5 kbar, with the 1 axis of [100] direction pressure, it turned out that it appears from about 3 kbar. Moreover, T0 is going up. This consistents with as a result of neutron scattering. [0 01] It combines with a direction and the experimental result under hydrostatic pressure, and performs thermodynamic consideration.