Field-Induced Magnetostructural Transitions in Antiferromagnetic   Fe1+yTe1-xSx
  The transport and structural properties of Fe1+yTe1-xSx (x=0, 0.05, and 0.10) crystals were studied in pulsed magnetic fields up to 65 T. The application of high magnetic fields results in positive magnetoresistance effect with prominent hystereses in the antiferromagnetic state. Polarizing microscope images obtained at high magnetic fields showed simultaneous occurrence of structural transitions. These results indicate that magnetoelastic coupling is the origin of the bicollinear magnetic order in iron chalcogenides. 
Masashi Tokunaga, Takumi Kihara, Yoshikazu Mizuguchi, Yoshihiko Takano
cond-mat.supr-con cond-mat.str-el