1211.1663 (T. J Liu et al.)

Exchange Field-Mediated Magnetoresistance in the Correlated Insulator
Phase of Be Films    [PDF]

T. J Liu, J. C. Prestigiacomo, Y. M. Xiong, P. W. Adams

We present a study of the proximity effect between a ferromagnet and a paramagnetic metal of varying disorder. Thin beryllium films are deposited onto a 5 nm-thick layer of the ferromagnetic insulator EuS. This bilayer arrangement induces an exchange field, $H_{ex}$, of a few tesla in low resistance Be films with sheet resistance $R\ll R_Q$, where $R_Q=h/e^2$ is the quantum resistance. We show that $H_{ex}$ survives in very high resistance films and, in fact, appears to be relatively insensitive to the Be disorder. We exploit this fact to produce a giant low-field magnetoresistance in the correlated insulator phase of Be films with $R\gg R_Q$.

View original: http://arxiv.org/abs/1211.1663