Magnetic structure of a UNiAl single crystal under pressure

Single-crystalline sample of UNiAl which orders antiferromagnetically below T-N = 19.3 K in a complex way (q = (0.1, 0.1 0.5)) has been investigated b y neutron diffraction under pressure up to 4.9kbar. Although electrical res istivity measurements reveal a drastic changed of the low-temperature trans port properties around 3 kbar suggesting a change of the magnetic-structure propagation we have not found any indication for such a change. As the pre ssure increases, U magneticmoment magnitudes decrease slightly and the magn etic structure gets less perfect. However, the antiferromaganetic structure of UNiAl remains stable in the whole temperature and pressure range studie d. (C) 2001 Elsevier Science BY. All rights reserved.