The suppression of Curie temperature by Sr doping in diluted ferromagnetic semiconductor (La1-xSrx)(Zn1-yMny)AsO

摘要

(La1-xSrx)(Zn1-yMny)AsO is a two dimensional diluted ferromagneticsemiconductor that has the advantage of decoupled charge and spin doping. Thesubstitution of Sr2+ for La3+ and Mn2+ for Zn2+ into the parent semiconductorLaZnAsO introduces hole carriers and spins, respectively. This advantageenables us to investigate the influence of carrier doping on the ferromagneticordered state through the control of Sr concentrations in(La1-xSrx)(Zn0.9Mn0.1)AsO. 10 % Sr doping results in a ferromagnetic orderingbelow TC ~ 30 K. Increasing Sr concentration up to 30 % heavily suppresses theCurie temperature and saturation moments. Neutron scattering measurementsindicate that no structural transition occurs for (La0.9Sr0.1)(Zn0.9Mn0.1)AsObelow 300 K.