The preparation of flexible Ni-Mn-In thin films on mica substrates by pulsed laser deposition

Abstract The large volume variation of ferromagnetic shape memory alloy is strongly restricted in the film format on rigid substrates. Due to the high growth temperature (>673 K), it is difficult to grow Heusler alloys with high crystalline quality on flexible polymers. We successfully synthesize high-quality 100 nm thick Ni51.6Mn33.5In14.9 films on transparent flexible mica substrates by pulsed laser deposition, and compare the crystalline structure, morphology and magnetic properties with the films grown on Si (1 0 0) substrates. Due to the weak Van der Waals inter-layer interaction in mica substrates, the clamping effect of substrate can be significantly weakened by thinning the thickness of substrates using the simple mechanical exfoliation. This makes the final sample with Ni-Mn-In film on ultrathin mica substrate highly flexible with smallest curvature radius down to 0.745 cm. In addition, the mechanical properties of flexible Ni-Mn-In films were tested by bending in various curvature radiuses repeatedly. The resistance only changes slightly after more than 10,000 cycles, indicating the highly stable flexibility. These results demonstrate that flexible ferromagnetic shape memory alloy film can be obtained by using mica substrates and has great potential applications in flexible electronics.