Large positive magnetoresistance in a novel superconductor Ca3+xCo4Sn13-y
Dr Monika Gamza
Finding new materials with large magnetoresistance (MR) has driven crucial progress in both solid state physics and device application. Well-known examples include giant MR in magnetic multilayers and colossal MR in Mn-based perovskites. For nonmagnetic systems, huge positive MR was seen in semiconductors with ultra–high carrier mobilities and in a number of semimetals. Recent studies on some of the latter systems led to discoveries of experimental realizations for various topologically nontrivial states such as Weyl or Dirac semimetals and brought this field to the forefront of quantum condensed matter research.
In this talk, I will introduce a novel superconductor Ca3+xCo4Sn13-y which shows a huge positive low temperature normal-state MR of up to 1000% in magnetic field of 9 T for crystals grown from Sn flux with the residual resistivity ratio (RRR) of 60-100. I will present results of structural, thermodynamic and transport measurements. With the help of the experimental data and electronic band structure results I will address the origin of the extraordinarily large MR. Finally, I will analyze the relationship between chemical composition and electronic properties for the ternary phase Ca3+xCo4Sn13-y.