In order to obtain improved magnetic track density, it is desirable to bring the read and write elements as close to the recording surface as possible, short of actually touching it. This has been achieved by utilizing a magnetostrictive actuator, comprising single or multiple pairs of magnetostrictive...http://www.google.es/patents/US7385789?utm_source=gb-gplus-sharePatente US7385789 - Magnetostrictive actuator in a magnetic head
