  Magnetoresistance and rectification are two fundamental physical properties
of heterojunctions and respectively have wide applications in spintronics
devices. Being different from the well known various magnetoresistance effects,
here we report a brand new large magnetoresistance that can be regarded as
rectification magnetoresistance: the application of a pure small sinusoidal
alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can
generate a significant direct-current voltage, and this rectification voltage
strongly varies with the external magnetic field. We find that the
rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large
as 250% at room temperature, which is greatly enhanced as compared with the
conventional magnetoresistance of 70%. The findings of rectification
magnetoresistance open the way to the new nonmagnetic Ge-based spintronics
devices of large rectification magnetoresistance at ambient temperature under
the alternating-current due to the simultaneous implementation of the
rectification and magnetoresistance in the same devices.
