Characterization of CrO2-poly-vinyl pyrrolidone magnetic nanofluid

► CrO2 nanoparticles and CrO2-poly vinyl pyrrolidone nanofluid are synthesized. ► Measurements of structural and magnetic parameters of the nanoparticles are done. ► Measurements of magneto-resistance and ultrasonic parameters of the nanofluid are done. ► Discussion is made for crystalinity of nanoparticles and magneto-resistance of the nanofluid. ► Discussion is also made for the factors/mechanisms responsible to the ultrasonic properties.