Magnetic properties of bicomponent nanoparticles CuO–CuFe$_2$O$_4$ obtained by arc evaporation method

Bicomponent CuO–CuFe$_2$O$_4$ nanoparticles with a CuFe$_2$O$_4$ content of about 20% were obtained using the arc evaporation method. X-ray examination showed that the samples contained only CuO nanoparticles with a size of 54 nm and CuFe$_2$O$_4$ with a size of 32 nm. The temperature dependences of the magnetization of nanoparticles $M(T)$ have a form characteristic of a superparamagnetic state with a blocking temperature above 400 K at $H$ = 100 Oe. The field dependences of the magnetization $M(H)$ show high values of saturation magnetization at all temperatures studied. In low fields, the $M(H)$ dependences have a hysteretic character, and at low temperatures the loop has features associated with different contributions to the magnetization from the central part of the bicomponent particle (CuFe$_2$O$_4$) and from the peripheral part adjacent to CuO. The synthesis method using an arc discharge makes it possible to effectively obtain bicomponent particles that are similar in size and with high magnetization values up to a temperature of 400 K.