news & views Nevertheless, a few hurdles must be overcome before SBA dielectrics will make a significant impact on large-scale transistor manufacturing. Perhaps the biggest problem at the moment is the slow response of the sodium ions to an external electric field. Consequently, the capacitance of the SBA films is reduced at higher frequencies. Solid-polymer electrolytes typically suffer from a...

The influence of Cu doping on phase transition, thermal strain, and expansion property polycrystalline Ni 50 Mn 23− x Ga 27 ( = 1, 3, 5, 6 7) alloys is investigated. results show that with increasing concentration, martensitic transformation gradually gets close to Curie transition. A magnetostructural transition (MST) observed in samples 7. Such MST can enhance magnitude strain. Besides, posse...

We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in a...

Ferromagnetic shape memory martensites in the Ni-Mn-Ga system have been demonstrated to achieve a number of the criteria required for next generation actuators including the production of large theoretical strains up to 6%. The large strain originates in the rotation of twin variants and associated twin boundary motion which occurs in response to magnetic fields. The magnetic activation holds p...

Polycrystalline Ni–Mn–Ga thin films have been deposited by the pulsed laser deposition ~PLD! technique, using slices of a Ni–Mn–Ga single crystal as targets and onto Si ~100! substrates at temperatures ranging from 673 K up to 973 K. Off-stoichiometry thin films were deposited at a base pressure of 1310 Torr or in a 5 mTorr Ar atmosphere. Samples deposited in vacuum and temperatures above 823 K...