Fracture toughness of VO2 microcrystals across metal-insulator transition

•Nanoindentation was performed on VO2 single crystals (011) at room temperature and 95 °C.•Decrease in crack length of about 40 % was observed after phase transition from monoclinic to tetragonal phase.•Fracture toughness of monoclinic phase was 2.02 ± 0.07 MPa.m1/2 and 2.67 ± 0.02 MPa.m1/2 for tetragonal phase. In this work, we report the fracture behavior of plate-shaped VO2 microcrystals across metal–insulator transition with the aid of in-situ nanoindentation at 25 °C and 95 °C. The fracture toughness of VO2 is found to be influenced by the thermal mismatch stress and transformation stress. The measured crack length generated from indentations is 40% lower after transition. The determined fracture toughness value for the monoclinic phase is 2.02 ± 0.07 MPa.m1/2, while it is 2.67 ± 0.02 MPa.m1/2 for the tetragonal phase.