Enhanced performance of Bi2Te3-based thermoelectric materials by incorporating Bi2Fe4O9 magnetic nanoparticles

•TE performance of P-type materials could be improved by incorporating Bi2Fe4O9 magnetic nanoparticles.•The maximum ZT value 1.1 was obtained at 393 K, which is 13% higher the pure sample.•The average ZT value was 0.98 in the temperature range of 303–483 K, exhibiting an increase of 11%.•Magnetic nanoparticles with low saturation magnetic moment.