Neutron diffraction study of the high magnetic field phase diagram of La-doped PrB6

Abstract

The high magnetic field phase diagram of lanthanum-doped PrB6 was investigated by single-crystal neutron diffraction. In this compound, a peculiar incommensurate phase denoted IC2 was observed in magnetic fields applied along directions close to [111]. Unlike the double-k IC1 phase [kIC1 = (1/4 − δ, ±1/4,1/2)] formed in zero field below TN = 7 K, IC2 is characterized by a propagation vector with two incommensurate components, kIC2 = (1/4−δ′, 1/4 − δ′, 1/2) (δ′ ≊ 0.03). The field and temperature evolutions of domain populations further indicate that, contrary to the low-field phases C and IC1, the magnetic structure in phase IC2 is single-k.