New method to improve the grain alignment and performance of thermoelectric ceramics

Textured Bi2Ca2Co1.7Ox ceramic rods were obtained by Electrically Assisted Laser Floating Zone (EALFZ) technique. The polarity effects of an external current, applied during the laser floating zone growth, have been investigated. Microstructure and thermoelectric properties have been studied and correlated with the current polarity. An important improvement of power factor was obtained for samples grown with the positive pole connected to the seed. This result evidences the advantages of EALFZ technique as a potential method for obtaining high performance thermoelectric materials.

► Cobaltites were grown by laser irradiation method applying electrical current.
► Microstructure and grain texture depend on the electrical current polarization.
► Electrical current polarization affects thermoelectric properties.