Effect of Magnetic Moment on Carrier Effective Mass and Transport in Magnetic Nd2Fe14B Composite Bi2Te3 Films.

ABSTRACT

A composite of magnetic and thermoelectric (TE) materials is one of the most popular methods to improve TE properties. However, the influential mechanism of the magnetic property on the carrier has not been clarified. In this study, Nd2Fe14B cylinders are used as the magnetic phase to regulate carrier behaviors in Bi2Te3 films. Roaming state Fe atoms in Nd2Fe14B provide some carriers. The VTe at the composite interface also provides carriers. These lead to the increase of carrier concentration and conductivity of the composite film. Meanwhile, the Lorentz force generated by the magnetic moment of Nd2Fe14B provides the carriers with a stronger energy, which results in the increase of carrier effective mass and thereby increases the Seebeck coefficient. Thus, the power factor of the magnetic composite film is improved by 366% compared with that of the pure Bi2Te3 film.