Ni–Mn–Ga thin films produced by pulsed laser deposition

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 are magnetic at room temperature and show the austenitic $220% reflection in their x-ray diffraction patterns. The temperature dependences of both electrical resistance and magnetic susceptibility suggest that these samples exhibit a structural martensitic transition at around 260 K. The magnetoresistance ratio at low temperature can be as high as 1.3%, suggesting the existence of a granular structure in the films. © 2002 American Institute of Physics. @DOI: 10.1063/1.1452222#