Enhanced low-field magnetoresistance in organic/inorganic glycerin/Sr2FeMoO6 composites

Low field magnetoresistance (LFMR) of double perovskite Sr2FeMoO6 (SFMO) is low at room temperature. In this paper, a low-cost, facile, and effective way to enhance the LFMR is developed. Single-phase SFMO ceramics with 10% Fe/Mo anti-site defects have been prepared, and then soaked in glycerin/water (1/1, V/V) mixture for 0-14 days. The insulating glycerin tends to segregate into the SFMO grain boundary to form organic/inorganic composite. Such a post-treatment has no effects on magnetic properties, but can increase the resistivity by ∼500 times, as the result, remarkable enhanced LFMR is observed in composites. With 0.5 T magnetic field, the LFMR of the SFMO soaked for 14 days reaches −29.5% at 10 K and −11.0% at 300 K, more than 2 times larger than that of the SFMO without soaking, which are −12.0% at 10 K and −4.7% at 300 K. Based on the experimental results, a possible mechanism is proposed to explain the relation between the composite structure and the LFMR response. We believe our work not only provides a novel method to enhance the magnetoresistance in SFMO ceramics, but also sheds light on tuning transport/magnetoresistance in other perovskite ceramics.