Experimental evidence of spin glass and exchange bias behavior in sputtered grown α-MnO2 nanorods

Abstract

Here, we present a single-step process to synthesize the α-MnO2 nanorods forest using reactive DC magnetron sputtering for the application of magnetic memories. The structural and morphological properties of the α-MnO2 nanorods were systematically studied using numerous analytical techniques, including X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy and transmission electron microscopy. The magnetic measurements suggest that the α-MnO2 nanorods exhibit spin glass and exchange bias behaviour at low temperature. Such low temperature behaviour is explained by the core-shell type structure of nanorods. Antiferromagnetic core and shell of uncompensated ferromagnetic spins leads to the formation of antiferromagnetic/ferromagnetic (AFM/FM) interfaces, which originates exchange bias in the sample.