Pressure induced collapse of the 4f-electron induced μ+-Knight shift in Sm0.9La0.1S

The pressure dependence of the μ+-Knight shift in the pseudo‐binary compound Sm0.9La0.1S has been studied with the aim to verify microscopically the quenching of paramagnetism by the formation and condensation of excitons in the insulating regime. A collapse of the μ+-Knight shift is indeed observed but it is not restricted to the insulating phase and may not reflect the bulk‐magnetic response.