Electrical and magnetic properties of spinel-type magnetic semiconductor ZnCo2O4 grown by reactive magnetron sputtering

We report on the growth of spinel ZnCo2O4 films using reactive magnetron sputtering and their electrical and magnetic properties, with particular emphasis on the relation of Curie-Weiss temperature (T-CW) and conduction type. The conduction type and carrier concentration in these films were found to be dependent on the oxygen partial pressure ratio in the sputtering gas mixture. The highest electron and hole concentration at 300 K were 1.37x10(20) and 2.81x10(20) cm(-3), respectively. A ferromagnetic coupling (T-CW>0) was observable in p-type ZnCo2O4, whereas an antiferromagnetic interaction (T-CW<0) was found for n-type and insulating ZnCo2O4, revealing hole-induced ferromagnetic transition in ZnCo2O4. (C) 2004 American Institute of Physics.