There is provided a head control device able to re-charge an electromechanical transducing element with a driving pulse without requiring an additional re-charging time period in a recording period. More particularly, the present invention provides novel nano sized particles of cerium sulfide as well as a novel process for the preparation of nano sized sulfide compounds of cerium by the bioreduction of cerium sulfate or cerium acetate, without resorting to chemical methods. , copper, into a fine interconnection pattern formed in a semiconductor substrate.