Insulator-to-metal transition and large thermoelectric effect in   La$_{1-x}$Sr$_{x}$MnAsO
  We report the Sr substitution effect in an antiferromagnetic insulator LaMnAsO. The Sr doping limit is $x\sim$ 0.10 under the synthesis conditions, as revealed by x-ray diffractions indicate. Upon Sr doping, the room-temperature resistivity drops by five orders of magnitude down to $\sim$0.01 $\Omega\cdot$cm, and the temperature dependence of resistivity shows essentially metallic behavior for $x\geq$0.08. Hall and Seebeck measurements confirm consistently that the insulator-to-metal transition is due to hole doping. Strikingly, the room-temperature Seebeck coefficient for the metallic samples is as high as $\sim240 \mu$V/K, making the system as a possible candidate for thermoelectric applications. 
Yunlei Sun, Jinke Bao, Chunmu Feng, Zhu'an Xu, and Guanghan Cao
cond-mat.str-el cond-mat.mtrl-sci