Evidence of 'CR' POT. 3+' and 'CR' POT. 4+' coexistence in chromium-doped 'SN''O' IND. 2' nanoparticles: a structural and magnetic Study - Aquino, Juan Carlos Romero; Herrera Aragón, Fermin Fidel; Coaquira, José Antonio Huamaní; Gratens, Xavier Pierre Marie; Chitta, Valmir Antonio; Gonzales, Ismael; Macedo, Waldemar A. A; Morais, Paulo C (Journal of Physical Chemistry C, 2017)