Magnetic susceptibility of <f>Ce0.75La0.25B6</f> under uniaxial pressure

Magnetic susceptibility <f>χ(T)</f> of the cubic compound <f>Ce0.75La0.25B6</f> has been examined under uniaxial pressures, focusing attention on the mysterious ordered state called ‘phase IV’. While being quite isotropic at an ambient pressure, <f>χ(T)</f> of phase IV becomes strongly anisotropic at a relatively weak pressure of <f>60 MPa</f> applied parallel to the [0 0 1] direction. A cusp remains at around the phase IV ordering temperature <f>To(≃1.7 K)</f> in <f>χ[1 1 0](T)</f> for magnetic field <f>H||[1 1 0]</f>, whereas <f>χ[0 0 1](T)</f> with <f>H||[0 0 1]</f> shows an upturn at <f>To</f> and continues to increase on further cooling. Surprisingly, <f>To</f> under the pressure seems to increase with <f>H||[0 0 1]</f>. The results cannot simply be explained by ordinary antiferromagnetic states, and are discussed in view of a possible multipolar ordering in phase IV. [Copyright &y& Elsevier]