Magnetization in insulating phases of Ti < sup > 4+ < /sup > -doped SrFeO < inf > 3-δ < /inf >

Abstract

SrFeO3-δ belongs to the Ruddlesden-Popper class of systems exhibiting interesting electronic and magnetic properties. Ti4+ -doped, oxygen-deficient SrFeO3-δ (SrFex Ti1-x O3-δ; x=0.9 and 0.7) samples show canted antiferromagnetic spin ordering, in contrast to the undoped sample (x=1) which is known to exhibit a metallic behavior with a helical spin arrangement. ac susceptibility Xac (f,T) at 10≤T≤300 K shows a frequency (100 Hz≤f≤10 kHz) -dependent temperature maximum, reminiscent of a spin-glass behavior. Increasing the Ti4+ content reduces the irreversibility, indicating a decrease in the frustration, which results in a diluted helical spin structure. Hysteresis loops can be associated with a gradual reorientation of spins in the field direction, indicating a canted type of spin arrangement. © 2006 American Institute of Physics.