The effects of rare earth site doping on the structural,superconducting and magnetic properties of SmFeAsO_(0.7)F_(0.3) iron pnictide are investigated.Gd^(3+)and Ce^(3+)ions are chosen by virtue of their position bein...The effects of rare earth site doping on the structural,superconducting and magnetic properties of SmFeAsO_(0.7)F_(0.3) iron pnictide are investigated.Gd^(3+)and Ce^(3+)ions are chosen by virtue of their position being on either side of Sm^(3+).Doping of both smaller(Gd^(3+))and larger(Ce^(3+))ions at the Sm^(3+)site increases the T_(C) up to 55 K.Doping with the smaller Gd^(3+)results in lattice contraction and thereby enhances T_(C).It is interesting to observe that though Ce^(3+)doping in SmFeAsO_(0.7)F_(0.3) exhibits an increase in lattice parameters,a substantial enhancement of T_(C) occurs.The enhancement in T_(C) due to increased charge carrier concentration is also confirmed using Hall Effect measurement.Apart from T_(C) enhancement,the simultaneous doping of both at oxygen and rare earth sites prominently increases the superconducting properties such as J_(C),H_(C1) and H_(C2).The co-doped samples also exhibit better magnetic field dependence of J_(C) over the entire field of study.It is also observed that the Ce^(3+)doped sample shows higher J_(C) in the high field region due to its enhanced flux pinning properties.展开更多
基金the Department of Science&Technology(DST)and CSIR 12th Five Year Plan Project,“Sustainable technologies for the Utilization of Rare Earths(SURE),”(no.CSC0132)for financial support.
文摘The effects of rare earth site doping on the structural,superconducting and magnetic properties of SmFeAsO_(0.7)F_(0.3) iron pnictide are investigated.Gd^(3+)and Ce^(3+)ions are chosen by virtue of their position being on either side of Sm^(3+).Doping of both smaller(Gd^(3+))and larger(Ce^(3+))ions at the Sm^(3+)site increases the T_(C) up to 55 K.Doping with the smaller Gd^(3+)results in lattice contraction and thereby enhances T_(C).It is interesting to observe that though Ce^(3+)doping in SmFeAsO_(0.7)F_(0.3) exhibits an increase in lattice parameters,a substantial enhancement of T_(C) occurs.The enhancement in T_(C) due to increased charge carrier concentration is also confirmed using Hall Effect measurement.Apart from T_(C) enhancement,the simultaneous doping of both at oxygen and rare earth sites prominently increases the superconducting properties such as J_(C),H_(C1) and H_(C2).The co-doped samples also exhibit better magnetic field dependence of J_(C) over the entire field of study.It is also observed that the Ce^(3+)doped sample shows higher J_(C) in the high field region due to its enhanced flux pinning properties.
